Optical disk apparatus

ABSTRACT

Functions regarding a mechanical structure are made common so as to enable both of a CD and an MO cartridge to be used by one apparatus. When the CD as an exposed medium is loaded, the apparatus operates as a CD player. When the MO cartridge as a cartridge enclosed medium is loaded, the apparatus operates as an optical disk drive.

BACKGROUND OF THE INVENTION

The invention relates to an optical disk apparatus for enabling the useof different optical disk media by one apparatus and, more particularly,to an optical disk apparatus for enabling the use of both of a compactdisc such as a CD-ROM or the like and a cartridge enclosed media such asa magneto-optical disk with a motor hub or the like by one apparatus.

A compact disc (CD) starting from an audio-use has been remarkablydeveloped in about ten years and can presently be regarded as a primarymultimedia component. Particularly, in recent years, a personal computerhaving therein a compact disc read only memory (hereinafter, simplyreferred to as a "CD-ROM") has rapidly spread. It is regarded that theposition of a CD player for reproducing a CD-ROM has been established asa third file device subsequent to a floppy disk drive (FDD) and a harddisk drive (HDD). On the other hand, a rewritable type optical diskapparatus using a magneto-optical disk enclosed in a cartridge is alsogradually spread by using advantages such that it has a large capacityand it is removable. The use of such a rewritable optical disk apparatusis also being progressed as a file device using a magneto-optical diskcartridge (MO cartridge) of 5 or 3.5 inches with a motor hub accordingto the ISO.

In a device using such a conventional optical disk media, however, anexclusive-use drive exists for every kind of the optical disk media suchas CD-ROM or MO cartridge. Therefore, when the user wants to use boththe CD-ROM and the MO cartridge, a CD player and an MO drive have to beseparately prepared. Particularly, in recent years, in many cases, theCD player or MO drive is built in the apparatus main body as aperipheral device of a personal computer. In such a case, it isdifficult in terms of the space to build two devices and there is aninconvenience such that only either one of the two devices can be builtin the apparatus main body. Toward a full-scale multimedia age, withrespect to the CD player, it is not limited to a function as a simplereproducing apparatus of the CD-ROM but a necessity of a rewritingfunction which has already been realized in the MO drive is stronglydemanded. With regard to the MO drive, on the other hand, it is notlimited to the use as a simple file device but it is strongly demandedthat the MO drive can cope with a CD-ROM, a video CD, and the like whichare provided as a part of the multimedia.

Particularly, when considering the MO drive, it is an indispensablecondition to make it possible to fetch CD resources provided in thefield of a personal computer which is rapidly being spread. In the CDplayer, in addition to a conventional CD-DA for music and a CD-ROM forreproducing dictionary data, an image data program, and the like, theedition and storage of a large capacity of data using those mediasimultaneously become the necessary conditions. On the other hand, theMO drive using the readable, writable, and further removable MOcartridge having a large capacity according to the ISO is also a devicethat is indispensable for processes of a large amount of data which isprovided by the CD-ROM or the like.

SUMMARY OF THE INVENTION

According to the invention, by paying attention to not only a point thateach of a CD player and an MO drive uses a laser diode for an opticalsystem but also a point that there are many similarities in a pickup, aservo control system, and the like, there is provided an optical diskapparatus of the CD/MO common use type in which functions of both ofthem, particularly, functions regarding a mechanism structure are madecommon and both of a CD and an MO cartridge can be used by oneapparatus.

According to the invention, there is provided an optical disk apparatushaving a common processing mechanism for commonly performing both of aprocess of a cartridge enclosed medium and a process of an exposedmedium which is not enclosed in a cartridge. The cartridge enclosedmedium is preferably a medium with a hub and the exposed medium is amedium without a hub. The exposed medium is, for example, a compact discand the cartridge enclosed medium is, for example, an optical diskcartridge in which an optical disk medium with a hub is enclosed. Anyother proper medium can be also used. When considering the compact disc(hereinafter, referred to as a "CD") and an optical disk cartridge(hereinafter, referred to as an "MO cartridge") in which amagneto-optical disk with a hub is enclosed, the common processingmechanism operates as a CD player when the CD is loaded and operates asan optical disk drive when the MO cartridge is loaded. A fundamentalconstruction of the apparatus comprises: an optical disk drive servingas an apparatus main body having an inserting/ejecting port for commonlyperforming an insertion and an ejection of the CD and the MO cartridge;a recording and reproducing mechanism, enclosed in the apparatus mainbody, for commonly performing a reproduction of the CD and the recordingand reproduction of the magneto-optical disk; a CD carrier on which theCD is mounted and performs a loading and an ejection to/from therecording and reproducing mechanism of the apparatus main body; and acircuit unit which operates as a CD player when the CD is loaded by theCD carrier and operates as a magneto-optical optical disk drive when theMO cartridge is loaded. The recording and reproducing mechanism has apickup mechanism for commonly performing an optical reproduction of theCD and optical recording and reproduction of the magneto-optical disk.

Since dimensional shapes of the CD and MO cartridge are different, thesetting of the dimensional relation between the CD carrier for mountingthe CD and the MO cartridge is important for commonly using the medium.With respect to such a relation, the invention has dimensional relationssuch that a thickness D2 of the CD carrier on which the CD is mounted isthinner than a thickness D1 of the MO cartridge and that a lateral widthW2 of the CD carrier to mount the CD is larger than a lateral width W1of the MO cartridge. An opening shape of the inserting/ejecting port ofthe apparatus main body is set to a shape adapted to such dimensionalrelations, thereby enabling the MO cartridge and the CD carrier to beinserted to a predetermined position of the inserting/ejecting port.That is, the inserting/ejecting port has an opening shape with astairway portion synthesized by making coincident the center positionsin the lateral width direction of the MO opening portion having thethickness Dand lateral width W1 of the optical disk cartridge and the CDopening portion having the thickness D2 and lateral width W2 of the CDcarrier. Specifically speaking, it is desirable that theinserting/ejecting port has an opening shape with a stairway portion ofa height difference of ΔD of about 1 mm in the thickness direction. Torealize such an opening shape of the inserting/ejecting port, byarranging a guide member for the opening portion having the thickness D1of the optical disk cartridge and the lateral width W2 of the CDcarrier, the center positions in the lateral width direction of the MOopening portion having the thickness D1 and lateral width W1 of theoptical disk cartridge and the CD opening portion having the thicknessD2 and lateral width W2 of the CD carrier are made coincide, therebyforming such an opening shape.

As an MO cartridge, for example, an MO cartridge of 3.5 inches accordingto the ISO is used. As a CD, a CD-ROM having a diameter of 120 mm or aCD-DA having a diameter of 120 mm is used. A CD-DA having a diameter of80 mm can be also used. Further, a digital versatile disc (DVD) can bealso used as a CD.

The invention relates to an optical disk apparatus which is connected toa controller and accesses to information stored in an optical diskmedium. As such an optical disk apparatus, the invention ischaracterized by comprising: a supporting member for rotatablysupporting a first optical disk medium enclosed in a cartridge and asecond optical disk medium mounted on a carrier; a loading mechanism forloading the cartridge and the carrier to the optical disk apparatus; asignal processing unit for optically reading information stored in theloaded optical disk medium and for converting into an electric signal; arotation control unit for controlling the rotation of the supportingmember; and an interface control unit for performing an interfacecontrol with a controller.

The cartridge is a cartridge formed according to the ISO 10090 and,specifically, a cartridge of a 3.5 inch type to enclose an MO diskmedium. As an MO disk medium, an MO disk medium having a plurality oftracks each having the same number of sectors can be used. Further, asan MO disk medium, an MO disk medium of a constant density type suchthat it is divided into a plurality of zones along a radial direction ofthe disk and each zone has a plurality of tracks and, as a number ofsectors in the track in each zone, the number of sectors in a zone onthe outer peripheral side is larger than that of the inner peripheralside can be similarly used. The supporting member is a carrier which canmount an optical disk medium of the read only type in which an outerdiameter is equal to 120 mm and information has been stored so that itcan be optically read. The optical disk medium is, for example, aCD-ROM. The optical disk medium has a plurality of sectors to storeinformation. A plurality of sectors are formed with physically the samelength in a range from the inner periphery to the outer periphery of theoptical disk medium.

The loading mechanism is a mechanism for acting on the side surface ofthe cartridge and for inserting/ejecting the cartridge and denotes amechanism for acting on the side surface of the carrier and forinserting/ejecting the carrier. The signal processing unit is a circuitfor forming a tracking error signal. When the CD-ROM is loaded, thetracking error signal forming circuit detects a tracking error signal bya heterodyne method. When the MO disk medium is loaded, the trackingerror signal forming circuit detects a tracking error signal by apush-pull method. The rotation control unit performs a rotation controlof the supporting mechanism so that an angular velocity is constant,namely, by the CAV control in case of the MO disk medium. When theCD-ROM is loaded, the rotation control unit can execute the rotationcontrol of the supporting mechanism in any of the constant linearvelocity control (CLV control) and the CAV control. The interfacecontrol unit is a control unit which can be switched to an SCSIinterface control for the MO disk medium or an ATP interface control forthe CD-ROM.

The above and other objects, features, and advantages of the presentinvention will become more apparent from the following detaileddescription with reference to the drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an explanatory diagram of a construction of an apparatus ofthe invention;

FIG. 2 is an explanatory diagram of the relation of the dimensionsbetween an MO cartridge and a CD carrier;

FIG. 3 is an explanatory diagram of a shape of an opening in aninserting/ejecting port of the invention;

FIG. 4 is an explanatory diagram of the front side of the CD carrier ofthe invention;

FIG. 5 is an explanatory diagram of the back side of the CD carrier ofthe invention;

FIG. 6 is a diagram for explaining the correspondence among a CD, the CDcarrier, and a spindle motor;

FIGS. 7A and 7B are explanatory diagrams of a CD turntable enclosed inthe CD carrier;

FIGS. 8A to 8D are explanatory diagrams of hub dimensions of the ISOwith which a hub of the CD turntable conforms;

FIG. 9 is an assembly exploded diagram of a casing of the apparatus;

FIG. 10 is an explanatory diagram of a main body unit which is enclosedin the inside;

FIG. 11 is an explanatory diagram of the back side of the main body unitof FIG. 10;

FIG. 12 is an explanatory diagram of a mechanism unit taken out from themain body unit of FIG. 10;

FIG. 13 is an explanatory diagram of the back side of the mechanism unitof FIG. 12;

FIG. 14 is an assembly exploded diagram of a casing of the main bodyunit of FIG. 10;

FIG. 15 is an explanatory diagram of a load motor assembly provided forthe main body unit of FIG. 10;

FIG. 16 is an assembly exploded diagram of a spindle assembly providedfor the mechanism unit of FIG. 12;

FIG. 17 is a side elevational view of the spindle assembly of FIG. 12;

FIG. 18 is an explanatory diagram of a pin switch for detection ofmedium information which is provided at an inserting/ejecting port ofthe main body unit of FIG. 10;

FIG. 19 is a correspondence diagram of a detection signal of the pinswitch in FIG. 10 and an identified medium;

FIG. 20 is an explanatory diagram at the start of the loading when an MOcartridge is inserted;

FIG. 21 is an explanatory diagram during the loading of the MOcartridge;

FIG. 22 is an explanatory diagram at the end of the loading of the MOcartridge;

FIG. 23 is an explanatory diagram at the start of the loading when a CDcarrier is inserted;

FIG. 24 is an explanatory diagram during the loading of the CD carrier;

FIG. 25 is an explanatory diagram at the end of the loading of the CDcarrier;

FIGS. 26A and 26B are block diagrams of a construction of a hardware ofthe invention;

FIG. 27 is a flowchart for the fundamental operation of the invention;

FIG. 28 is a block diagram of a host interface of the invention;

FIG. 29 is a flowchart for processes of an MPU in response to aninterruption of a host command in FIG. 28;

FIG. 30 is a block diagram of a tracking error detecting circuit of theinvention;

FIG. 31 is a block diagram of a tracking error detecting circuit for aCD in FIG. 30;

FIGS. 32A and 32B are time charts of tracking error signals at the timesof a low-speed seek and a high-speed seek in FIG. 27;

FIG. 33 is a block diagram of a tracking error detecting circuit for anMO in FIG. 30;

FIG. 34 is a block diagram of a spindle control circuit for enabling aCAV control and a CLV control to be switched;

FIGS. 35A and 35B are explanatory diagrams of the relation between atrack position in the CLV control and a rotational speed and therelation between the track position in the CAV control and a read clockfrequency;

FIG. 36 is an explanatory diagram of mode information for designatingthe CAV/CLV switching and a speed switching in accordance with the kindof medium according to the invention;

FIG. 37 is an explanatory diagram of a frequency dividing ratio, afilter constant, and a gain which are used in the CAV control;

FIG. 38 is an explanatory diagram of a times-speed designation, a filterconstant, and a gain which are used in the CLV control;

FIG. 39 is a flowchart for a set-up process in association with theloading of a medium;

FIG. 40 is a flowchart for a set-up process of an MO spindle control;

FIG. 41 is a flowchart for a set-up process of a CD spindle control;

FIG. 42 is a flowchart for staging for a cache of medium data in theset-up process;

FIG. 43 is a flowchart for an error retrying process for coping with theoccurrence of a read error of the CD by switching a spindle rotation toa low speed or by switching from CAV to CLV;

FIG. 44 is an explanatory diagram of switching characteristics of aninner CLV control and an outer CAV control according to the trackposition of the CD;

FIG. 45 is a flowchart for a switching control of CAV and CLV in FIG.44;

FIG. 46 is a speed characteristics diagram according to track positionsat the normal speed and the 4-times speed in the CLV control of the CD;

FIG. 47 is an explanatory diagram of switching characteristics of theinner CAV control and the outer CLV control according to the trackposition of the CD; and

FIG. 48 is a flowchart for a switching control of CAV and CLV in FIG.47.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

[Construction of Apparatus]

FIG. 1 is an explanatory diagram of an optical disk apparatus of theinvention. The optical disk apparatus of the invention has an opticaldisk drive 10 serving as an apparatus main body and can use either oneof a magneto-optical disk cartridge (hereinafter, simply referred to asan "MO cartridge") 12 and a compact disc (hereinafter, simply referredto as a "CD") 14 as a medium by the optical disk drive 10. The opticaldisk drive 10 has a size of, for example, a height of 25.4 mm, a widthof 146 mm, and a depth of 190 mm. For example, a rewritable cartridgeaccording to the ISO can be used as an MO cartridge 12 and any one ofcapacities of 128 MB, 230 MB, 540 MB, 640 MB, and the like can be used.As a cartridge other than those, a cartridge of 230 MB, 540 MB, 640 MB,or the like of a 3.5-inch MSR cartridge (1 GB) or a 3.5-inch MOoverwrite cartridge (which will conform with the ISO) can be used. Forexample, as an MO cartridge 12, there is used a cartridge according to"90 mm rewritable and read-only type optical disk cartridge" of JIS X6272 (settled on Sep. 1, 1992) according to ISO/IEC 10090 (Informationtechnology -90 mm optical disk cartridges, rewritable and read only, fordata interchange issued 1990). As a CD 14, a CD-ROM (model 1, 2) of 120mm, a CD-DA of 120 mm, and a photo CD of 120 mm (single session andmulti-session) can be used. Further, a CD-DA of 80 mm can be alsoreproduced. In future, a DVD (digital versatile disk in which the unitedstandard was determined on Dec. 8, 1995) as a video disk of the nextgeneration of digital motion picture can be also used. For example, adisk according to "Compact disc read only memory system description"(May, 1985, Sony Corporation and N.V. Philips Co., Ltd.) published as aninternal reference of Sony Corporation and Philips Co., Ltd. is used.

A door 20 which is rotatable around a lower portion as a rotationalcenter is provided in the front side of the optical disk drive 10. Byopening the door 20, an inserting/ejecting port 18 is opened. As shownin FIG. 9, an ejection switch knob 22, a volume dial 25 for adjusting asound volume upon reproduction of the CD 14, and further a necessaryindicator are provided for the front panel portion of the optical diskdrive 10. The MO cartridge 12 can be inserted as it is into the opticaldisk drive 10 and can record and reproduce. On the other hand, the CD 14is mounted to a CD carrier 16 and is inserted into the optical diskdrive 10. The CD carrier 16 is a holder member which is opened to theupper portion. The CD carrier 16 rotatably has the CD turntable 24 atthe center of a CD enclosing unit 15 having a circular concave portion.The CD 14 is mounted onto the CD turntable 24 so that an attaching hole48 of the CD 14 is fitted to the CD turntable 24. A rectangular openingportion 30 corresponding to a seeking region of the CD 14 is opened at apredetermined position of the CD enclosing unit 15, thereby exposing amedium surface on the lower side of the CD 14.

FIG. 2 shows a comparison of edge surfaces on the inserting side of theCD carrier 16 for mounting the MO cartridge 12 and CD 14 in FIG. 1 forthe optical disk drive 10. The MO cartridge 12 has standard dimensionsbased on the ISO of a thickness D1 (=6.0±0.2 mm) and a lateral width W1(=90.0 mm) (tolerance lies within a range from 0 to -0.4 mm). On theother hand, the CD carrier 16 has a thickness D2 and a lateral width W2in correspondence to the CD 14 having a diameter of 120 mm. There is thefollowing dimensional relation of

    D1>D2

between the thickness D1 of the MO cartridge 12 and the thickness D2 ofthe CD carrier 16. For example, the MO cartridge 12 has the thickness D1(=6 mm) according to the ISO. On the other hand, a thickness of CD 14which is mounted onto the CD carrier 16 is set to 1.2 mm on the basis ofthe united standard of Sony and Philips and D2 is set to 4.5 mm as athickness such that the CD can be sufficiently enclosed in the CDcarrier 16. Therefore, a dimensional difference of about 1 mm in thethickness direction exists between the thickness D1 of the MO cartridge12 and the thickness D2 of the CD carrier 16.

As shown in FIG. 1, the MO cartridge 12 and CD carrier 16 (on which theCD 14 is mounted) whose sizes are different are inserted and ejectedto/from the optical disk drive 10 of the invention by using the sameinserting/ejecting port 18. Therefore, an opening portion of theinserting/ejecting port 18 has a shape, a position, and a dimensionalrelation as shown in FIG. 3. In FIG. 3, the inserting/ejecting port 18of the optical disk drive 10 has an opening portion 18-2 for CD of thethickness D2 and lateral width W2 corresponding to the CD carrier 16 inFIG. 2. An opening portion 18-1 for MO having the thickness D1 andlateral width W1 of the MO cartridge 12 in FIG. 2 is overlappinglyformed while making a center position coincide with the center in thelateral width direction of the opening portion 18-2 for CD. Thus, aneffective opening portion of the inserting/ejecting port 18 for the MOcartridge 12 and CD carrier 16 has a stairway opening shape such that anupper portion has the lateral width W1, a lower portion has the lateralwidth W2, and a shape in the thickness direction is dented with thelateral width W1 by only a thickness of ΔD (=D1-D2) from the upper sideand is widened to the lateral width W2 with the thickness D2 after that.In the actual apparatus, a rectangular opening portion having a heightof the thickness D1 of the MO cartridge 12 and the lateral width W2 ofthe CD carrier 16 is provided. With respect to such a rectangularopening portion, a guide member to form the opening portion 18-1 for MOwhich is dented with the lateral width W1 at the center by only ΔD isprovided. By forming such an opening shape of the inserting/ejectingport 18 in FIG. 3 adapted to the thickness and lateral width in theinserting direction of the MO cartridge 12 and CD carrier 16, both ofthe MO cartridge 12 and the CD carrier 16 on which the CD 14 is mountedcan be inserted and ejected to/from the inserting/ejecting port 18. Atthe same time, the MO cartridge 12 and CD carrier 16 can beunconditionally positioned at the inserting/ejecting port 18,respectively.

[CD Carrier]

FIG. 4 shows the CD carrier which is used in the invention. FIG. 5 showsthe back side thereof. In FIGS. 4 and 5, in the CD carrier 16, arectangular holder 26 formed by an injection molding of plastics is usedas a main body and the CD enclosing unit 15 having a circular concaveportion adapted to enclose the CD 14 is formed in the upper portion ofthe holder 26. The CD turntable 24 is rotatably enclosed at the centerof the CD enclosing unit 15. An opening portion 30 is formed in thebottom surface on the inserting side of the CD enclosing unit 15,thereby exposing the recording surface of the CD 14 mounted to the CDturntable 24 to the lower side. In a state in which the CD carrier 16 isloaded to the optical disk drive 10 in FIG. 1, a pickup mechanism islocated at the lower position which faces the opening portion 30. Guidespring portions 50, 52, 54, and 56 are projected at four upper cornersof the holder 26 surrounding the CD enclosing unit 15. The guide springportions 50, 52, 54, and 56 prevent shaking, a floating, curving, or thelike of the holder 26 when the CD carrier 16 is inserted to the opticaldisk drive 10 in FIG. 1 and enable the movement for loading or ejectingwith the posture and position held in the optical disk drive 10. A taperguide portion 32 is provided for the right corner portion on theinserting side of the holder 26. The taper guide portion 32 forms aroller pull-in surface to pull in such that a loading roller of aloading mechanism first comes into contact with the taper guide portion32 when the CD carrier 16 is inserted into the optical disk drive 10 andpulls in the CD carrier 16. An arm escaping groove 34 is formed on theleft side of the taper guide portion 32. A function of the arm escapinggroove 34 will be clarified in the description of the loading mechanism,which will be obviously explained hereinlater. A reverse insertionpreventing pin 38 is projected and formed at one position of the cornerportions on the inserting side and ejecting side of the holder 26. Thereverse insertion preventing pin 38 prevents the CD carrier 16 frombeing inserted into the optical disk drive in a state in which the frontand rear sides are reversed. At the time of the normal insertion, bypushing out the loading roller and moving to the outside by the obliquesurface of the taper guide portion 32, the CD carrier 16 is loaded.However, at the time of the reverse insertion, since the CD carrier 16collides with the loading roller by the corner portion of the leftopposite surface of the taper guide portion 32, the loading cannot beperformed, thereby preventing the reverse insertion. Positioning holes40 and 42 and a carrier detecting hole (medium detecting hole) 44 areformed in the CD enclosing unit 15 of the holder 26. The positioningholes 40 and 42 are formed at the same positions and in the same shapesas those of the positioning holes formed similarly in the MO cartridge12 when the rotational center of the MO cartridge 12 in FIG. 1 ispositioned to a rotational center which is determined by the CDturntable 24. The carrier detecting hole 44 is a detecting hole that ispeculiar to the CD carrier 16. Therefore, the optical disk drive 10 sidecan identify whether the inserted medium is the MO cartridge 12 or theCD carrier 16 on which the CD 14 is mounted on the basis of the presenceor absence of the carrier detecting hole 44. Namely, it will beunderstood that when the carrier detecting hole 44 can be detected, theinserted medium is the CD 14, and when the carrier detecting hole 44cannot be detected, the inserted medium is the MO cartridge 12. Further,the rewritable MO cartridge has a slide knob to select the inhibitionand permission of the rewriting operation. However, since the CD 14 is aread only disc, no hole is formed in the portion corresponding to theopening portion to decide the presence or absence of the permission ofthe writing operation in order to inhibit the rewriting operation. TheCD turntable 24 arranged at the center of the CD enclosing unit 15 ofthe holder 26 integratedly has a CD side hub 70 in the upper portion ofa disk 68 with a flange and also has latch balls 76 at three peripheralpositions of the CD side hub 70. On the back side of the CD turntable24, as shown in FIG. 5, a spindle side hub 62 is integratedly providedat the center of the disk 68 with the flange. As a spindle side hub 62,the same hub as the hub used in the magneto-optical disk enclosed in theMO cartridge 12 is used.

FIG. 6 shows a state in which the CD 14 is attached to the CD carrier 16and also shows a coupling relation upon loading to a spindle motor 60built in the optical disk drive 10. The CD 14 has the attaching hole 48at the center and the attaching hole 48 is fitted to the CD side hub 70of the CD turntable 24 provided at the center of the CD carrier 16. Asmentioned above, when the CD carrier 16 is inserted into the opticaldisk drive 10 in an attaching state of the CD 14, the CD carrier 16 isautomatically loaded to the spindle motor 60. When the CD carrier 16 ismoved to the loading position corresponding to the rotational center ofthe spindle motor 60, the spindle motor 60 side is lifted up, therebycoupling with the spindle side hub 62 on the back side in FIG. 5 of theCD turntable 24 by a magnetic force of a magnet.

FIG. 7A shows an enclosing state of the CD turntable 24 to the center ofthe holder 26 of the CD carrier 16 in which the CD 14 is mounted. The CDturntable 24 has the CD side hub 70 in the upper portion of the disk 68with flange in which the flange is formed by the dented portion of theouter periphery. Enclosing holes 74 are opened at three positions of theside surface of the CD side hub 70 and only one enclosing hole 74 isshown as a representative. A latch ball 76 is enclosed in the enclosinghole 74 through a spring 78. The opening portion of the enclosing hole74 is formed smaller than a diameter of latch ball 76, thereby enablingthe latch ball 76 to be held in a state in which a front edge isremoved. By depressing the attaching hole 48 of the CD 14 from the upperportion to the CD side hub 70 as mentioned above, the latch ball 76 ismoved backward into the enclosing hole 74 against a force of the spring78, so that the CD 14 comes into contact with a table surface 72 of theupper portion of the disk 68 with the flange shown in the diagram and isfixedly attached in a state in which the upper edge of the openingportion of the attaching hole is pressed by the latch ball 76. The tablesurface 72 of the disk 68 with the flange on which the CD 14 is mountedis coated with a rubber or the like in order to prevent slipping of theCD. A thickness of such a coating layer is extremely thin on the micronorder. The coating layer prevents the slipping of the CD 14 mounted onthe disk 68 with the flange without losing surface precision of thetable surface 72, thereby preventing deviation of the CD 14 due to therotation of the CD turntable 24. The spindle side hub 62 is provided inthe lower portion of the disk 68 with the flange provided for the CDturntable 24. A shaft inserting hole 66 to insert the rotary shaft ofthe spindle motor is formed at the center of the spindle side hub 62. Amagnetic plate 64 using an iron plate is provided around the peripheryof the hole 66. The spindle side hub 62 has the same structure, shape,and dimensions as those of the hub attached to the magneto-optical diskenclosed in the MO cartridge 12 in FIG. 1. A turntable enclosing unit 45is formed in the center portion of the CD carrier 16 by a holding plate46 attached to the lower side. The dented flange portion of the disk 68with the flange is located in the vertical closed portion of theturntable enclosing unit 45, thereby preventing the CD turntable 24 frombeing dropped from the CD carrier 16.

FIG. 7B shows a state in which the CD carrier 16 is loaded to thespindle motor. In the loading state, a motor rotary shaft 84 of thespindle motor is fitted into the shaft inserting hole 66 of the spindleside hub 62 of the CD turntable 24. A motor hub 80 is fixed to the motorrotary shaft 84. A magnet 82 is attached to the inner upper surface ofthe motor hub 80. By arranging the magnet 82 in close vicinity with themagnetic plate 64 of the spindle side hub 62, the CD turntable 24 andmotor hub 80 are magnetically coupled, so that the CD 14 attached to theCD turntable 24 can be rotated in association with the rotation of themotor rotary shaft 84. In the loading state, the disk 68 with the flangeof the CD turntable 24 is located in the turntable enclosing unit 45 ina floating state and can be rotated without coming into contact with theCD carrier 16 side.

FIGS. 8A to 8D show dimensions of the hub of ISO/IEC 10090 (JIS X6272⁻¹⁹⁹²) with which the spindle side hub 62 provided for the CDturntable 24 in FIGS. 7A and 7B conform. A magnetic material 602 isarranged around a center hole 604 and a hub 600 in FIG. 8A is arrangedon one side of a disk 610. A diameter D5 of the center hole 604 of thehub 600, an outer diameter D6, a height h1 from the disk surface, aposition h2 of the magnetic surface from the disk surface, a height h3from a reference surface P to the upper portion of the center hole 604,and a height h4 of the center hole 604 are as shown in FIG. 8B. Achamfer c1 of 45°0 and 0.2±0.1 mm is formed at the inner corner of thecenter hole 604 or such a corner is set to a curvature of a radius R16(=0.4±0.1 mm). An outer diameter D9 and an inner diameter D10 of themagnetic material 602 to clamp the disk 610 are as shown in FIG. 8C.Further, an outer diameter D7 and an inner diameter D8 of a clampingzone are as shown in FIG. 8D.

[Mechanism Structure of the Main Body]

FIG. 9 is an assembly exploded diagram of a casing of the optical diskdrive 10 in FIG. 1. A main body casing 86 is a box-shaped member whichis opened toward the front side and the upper side. A panel unit 92 isattached to the front portion of the main body casing 86. The panel unit92 has the door 20 which is closable in the pull-down direction and theejection switch knob 22. The volume dial 25 and an ejection switch 27are attached on the main body casing 86 side corresponding to theattaching position of the panel unit 92. A main body unit 100 in FIG. 10is attached to the main body casing 86. A printed circuit board 88 isarranged in the upper portion in a state in which the main body unit 100is attached to the main body casing 86. A circuit with a hardwareconstruction of the optical disk drive 10, which will be explainedhereinlater, is installed on the printed circuit board 88. A connector94 is provided in the rear portion. Further, a rectangular bias magnetrefuging hole 96 is opened at the center of the printed circuit board88. Subsequent to the printed circuit board 88, a cover 90 is attachedto the upper portion.

FIG. 10 shows the main body unit 100 which is enclosed in the main bodycasing 86 in FIG. 9 when it is seen from the upper side. In the mainbody unit 100, the lower side becomes the medium inserting/ejecting port18 side. A mechanism unit 101 is attached to the main body unit 100 fromthe rear portion as shown by a broken line. A part of the rear portionof the mechanism unit 101 is exposed and FIG. 12 shows the mechanismunit 101. As shown in an assembly exploded diagram of FIG. 14, the mainbody unit 100 is constructed by: a fixed assembly 115 which is arrangedin the upper portion; a fixed assembly 164 which is provided on theinserting/ejecting port side; a side plate 166 which is attached to theright side of the fixed assembly 115; and a load plate 130 which isarranged in the lower portion on the left side of the fixed assembly 115through an intermediate plate 128 and is movable in theinserting/ejecting direction of the medium. In the assembly state of themain body unit 100 in FIG. 10, a guide groove 102 is formed on the uppersurface of the fixed assembly 115 in the depth direction from theinserting/ejecting port 18 side. A shutter pin 104 is arranged at aninitial position of the guide groove 102 before the medium is loaded.The shutter pin 104 moves the guide groove 102 in the depth direction inassociation with the loading of the MO cartridge 12 or CD carrier 16. Bythe motion in the lateral direction of the shutter pin 104 in thisinstance, in case of the MO cartridge 12, the shutter is released at theloading completion position. A bias magnet holder 106 serving as acantilever door by a shaft 108 is supported on the center rear side ofthe upper surface of the fixed assembly 115 serving as a left side ofthe guide groove 102. The bias magnet holder 106 is urged by a coilspring 110 in such a direction as to close the door. A bias magnet 107is attached to the inside of the bias magnet holder 106 so that a partof the bias magnet 107 can be seen in FIG. 11 showing the back side ofthe fixed unit 100 in FIG. 10. The bias magnet 107 generates an externalmagnetic field when erasing the magneto-optical disk enclosed in theloaded MO cartridge 12. The bias magnet 107 is unnecessary when the CD14 mounted on the CD carrier 16 is loaded. To erase the MO cartridge 12,the bias magnet 107 is projected to the inside of the fixed assembly 115and is positioned within the specified dimensions for the medium surfaceof the magneto-optical disk. When the CD carrier 16 on which the CD 14was mounted is loaded, therefore, the bias magnet holder 106 to whichthe bias magnet 107 was attached to the inside is pushed up by the CDcarrier 16 and is shunted to the outside, thereby preventing it frombecoming an obstacle in the reproduction of the loaded CD 14 by the CDcarrier 16. In correspondence to the bias magnet holder 106, as shown inFIG. 9, the bias magnet refuging hole 96 is opened to the printedcircuit board 88 locating in the upper portion. A load motor 112 isattached to the right side of the inserting/ejecting port 18 of thefixed assembly 115. The load motor 112 has a load roller guide groove114 for positioning a load roller in a loading mechanism, which will beobviously described hereinlater, in accordance with a size of mediumthat is loaded.

In FIG. 11, when the main body unit 100 is seen from the back side, amotor assembly 124 is arranged at an approximate center. The motorrotary shaft 84 is located at the center of the motor assembly 124. VCMcoils 120 and 122 of a carriage 118 serving as a movable portion of apickup are arranged in the upper portion of the motor assembly 124 so asto be movable in the front/rear direction along yokes 121 and 123 of theVCMs arranged on both sides. A fixed optical unit 116 of the pickup isarranged at a depth position which faces the carriage 118. An objectivelens, a lens actuator for rotating the objective lens around thehorizontal direction and for tracking a beam, and a focusing coil formoving the objective lens in the direction of an optical axis and forperforming an automatic focusing control are mounted on the carriage118. The other units of the optical system are provided on the fixedoptical unit 116 side in order to reduce weight. When viewed from theback side in FIG. 11, the load plate 130 shown in FIG. 14 is assembledto the fixed assembly 115 so as to be movable in the front/reardirection as a part portion in the vertical direction locating on theright side from a part portion in the lateral direction locating on theinserting/ejecting port 18 side by fitting pins 154 and 156 into guideholes 152 and 157 for the fixed assembly 115. The position of the loadplate 130 is a first position serving as an initial state in which theMO cartridge 12 or CD carrier 16 is not loaded. Coil springs 158 and 160are provided between the load plate 130 and the fixed assembly 164located on the inserting/ejecting port 18 side, thereby pulling the loadplate 130 to the inserting/ejecting port 18 side. Further, similar coilsprings are also provided between the intermediate plate 128 in FIG. 14and the load plate 130, thereby pulling the load plate 130 to theinserting/ejecting port 18 side. After completion of the loading of theMO cartridge 12 or CD carrier 16, a retaining of the load plate 130 by astopper 244 of an arm member, which will be clearly describedhereinlater, is released by the rotation of the arm around a shaft 150as a center. A locked state of an edge portion 131 of the load plate 130by the stopper 244 is released. Thus, the operation to slide the loadplate 130 to the inserting/ejecting port 18 side by the springs 158 and160 by only an amount corresponding to lengths of guide holes 148, 152,and 157 is executed. The position by the sliding of the load plate 130by the completion of the loading is set to the second position. When alatching of the load plate 130 is released by the completion of theloading and the load plate 130 is slid from the first position (initialposition) to the second position, since a guide assembly 206 has beencoupled to the load plate 130 through links 136 and 138, the guideassembly 206 is also slid toward the inserting/ejecting port 18 sidethrough the links 136 and 138 together with the load plate 130. By thesliding of the guide assembly 206 that is interlocked with the loadplate 130, a lifting operation of an elevating mechanism of the spindlemotor, which will be obviously described hereinlater, is executed. Bythe lifting operation of the spindle motor, a spindle is attached to amedium of the MO cartridge 12 or the CD mounted on the CD carrier 16after completion of the loading. An ejection motor 126 is mounted on thefixed assembly 164 locating on the inserting/ejecting port 18 side. Arotational force of the ejection motor 126 is transferred to a cam gear140 by a gear train 134. A cam 146 is provided on the cam gear 140. Theinserting/ejecting port 18 side of the load plate 130 is stopped at aposition near a rotary shaft of the cam gear 140 as shown at 130' in asliding state to the second position after completion of the loading. Inthis state, when the ejection motor 126 is driven and the cam gear 140is rotated counterclockwise, the load plate 130 is pushed back to theinherent first position by a rotation of the cam 146. At the same time,a member of the motor assembly 124 is also returned to the inherentposition through the links 136 and 138. Therefore, the coupling of thespindle motor is released by the down-operation of the motor elevatingmechanism. Further, by returning the front edge portion 131 of the sideedge of the load plate 130 to the first position, the medium can beejected and can be returned to the retaining state by the stopper 244. Acarriage stopper 117 is attached to the back surface side of the rotaryshaft 150 of the arm member in FIG. 11. The carriage 118 is stopped atthe initial position on the fixed optical unit 116 side in an initialstate. When the carriage 118 is located at the initial position, aportion at a right edge of the carriage 118 locating in the VCM coil 122is retained by a claw portion of the front edge of the carriage stopper117. When the medium is loaded, the carriage stopper 117 iscounterclockwise rotated by the rotation of the arm member, therebyreleasing the retaining of the carriage 118. The main body unit 100 inFIG. 11 other than the above construction will be described withreference to the diagrams as necessary when each portion is described indetail.

FIG. 12 shows a state when the mechanism unit 101 enclosed on the rearportion side of the main body unit 100 in FIGS. 10 and 11 is taken outand seen from the upper portion. FIG. 13 is a diagram showing themechanism unit 101 in FIG. 12 when it is seen from the back side. In themechanism unit 101, the motor rotary shaft 84 and motor hub 80 areprovided in the upper portion of the spindle motor 60. The hub of themagneto-optical disk in the MO cartridge 12 which was loaded or thespindle side hub of the CD turntable 24 on which the CD 14 mounted onthe CD carrier 16 is attached is located in the upper portion of themechanism unit 101. Subsequent to the spindle motor 60, the carriage 118of the pickup is provided so as to be movable in the depth direction bythe VCM coils 120 and 122. An actuator unit 165 is mounted on thecarriage 118 and an objective lens 162 is exposed to the upper portion.The objective lens 162 is moved in the horizontal direction by abuilt-in lens actuator (4-spring supporting method), thereby controllinga beam position for the disk medium surface. On the other hand, when theobjective lens 162 is moved in the vertical direction serving as anoptical axial direction, a focusing control is performed. In the controlof the beam position by the movement of the carriage 118 by the VCMcoils 120 and 122, when a seek distance from the present track positionto the target track position is long, the carriage 118 is driven. On theother hand, when the seek distance is so short to be, for example, ±50tracks for the present track position, a seek control by a high-speedtrack jump is performed by the horizontal movement of the objective lens162 by the lens actuator. When the beam seeking operation is finished bythe movement of the objective lens 162 by the lens actuator, a positioncontrol by the VCM coils 120 and 122 of the carriage 118 is performed ina manner such that a lens position detection signal (LPOS) from aposition detector for detecting a neutral position of the lens actuatorbuilt in the actuator unit 165 becomes a detection signal indicative ofa zero-point position. Such a position control by the lens actuator andthe VCM is called a "double servo".

FIG. 13 is a diagram of the mechanism unit 101 when it is seen from theback side. A structure on the bottom surface side of the elevatingmechanism of the spindle motor by the links 136 and 138 for the motorassembly 124 will be obviously understood from this diagram.

FIG. 15 shows a load motor assembly 170 provided on the right side ofthe inserting/ejecting port 18 of the main body unit 100 in FIG. 10. Inthe load motor assembly 170, the load motor 112 is attached onto a fixedplate 171. A rotary plate 182 is rotatably attached on the lower side toa fixed shaft 180 attached to the fixed plate 171. A shaft 185 isattached to the rotational side of the front edge of the rotary plate182. A belt pulley 178 is provided for the fixed shaft 180 serving as afulcrum of the rotary plate 182. A belt pulley 184 is also provided forthe shaft 185 on the rotational side. A belt 188 is wound between bothof the belt pulleys 178 and 184. A load roller 186 is integratedlyprovided for the belt pulley 184 on the front edge side of the rotaryplate 181. The load roller 186 frictionally comes into contact with theside surface of the MO cartridge 12 or CD carrier 16 which was insertedby the operator, thereby performing a pull-in operation for loading. Forthis purpose, a rubber roller is used as a load roller 186 in order toobtain enough frictional force. A coil spring 190 is attached to thefixed shaft 180. One end of the coil spring 190 is retained to the fixedplate 171 side and the other end is retained to the belt pulley 184side. By the coil spring 190, the rotary plate 182 is urgedcounterclockwise, thereby enabling the load roller 186 to be alwayspressed against the medium side which is located on the inside. By alateral width of the medium locating on the inside, the rotary plate 182rotates around the fixed shaft 180 as a center. Even if the position ofthe medium side surface changes, the load roller 186 can be pressedagainst the medium side surface in accordance with the position. Arotational force by a gear train 176 shown in the diagram is transferredfrom the load motor 112 to the belt pulley 178 of the fixed shaft 180.By further inserting pins 196 and 199 into guide grooves 194 and 198,the movable plate 195 is supported to the inside for the fixed plate 171so as to be movable in the front/rear direction. A load switch 172 isattached onto the fixed plate 171. The load switch 172 has a switch knob174 in the upper portion. The load switch 172 is a change-over switchwhose switch contact is switched in dependence on the position of theswitch knob 174. Before the medium is loaded, the switch knob 174 islocated at a position as shown in the diagram. When the operator insertsthe medium in this state, the front edge of the medium comes intocontact with the switch knob 174, and which falls down, therebyactivating the load motor 112 at this switching position and performingthe pull-in operation for loading the medium by the clockwise rotationof the load roller 186. When the medium reaches a loading completionposition, the load plate 130 described with reference to FIG. 11 is slidfrom the first position before loading to the second position by thecompletion of the loading. In this state, when the ejecting operation bythe rotation of the ejection motor 126 in FIG. 11 is executed, the loadplate 130 is pushed back to the first position, the coupling with thespindle motor is released, and pin switches 222, 224, and 226 are alsoaway from the medium. Since all of the pin switches 222, 224, and 226are away from the medium, the load motor 112 is activated so as toreversely rotate and rotates the load roller 186 counterclockwise. Afeeding operation to feed the ejected medium to the inserting/ejectingport 18 by the load roller 186 can be executed. Namely, the load motor112 of the load motor assembly 170 executes both of the loadingoperation when the medium is inserted and the ejecting operation aftercompletion of the ejection at the time of the ejection of the medium.

FIG. 16 is an assembly exploded diagram of the motor assembly 124 inFIGS. 11 and 12. In the motor assembly 124, the spindle motor 60 ismounted on a lifter 200. The motor rotary shaft 84 and the motor hub 80having a magnet are rotatably provided in the upper portion of thespindle motor 60. Cut-standing portions are formed at four positions oflifters 200 on both sides of the spindle motor 60. Pins 202 and 204 areprovided for the cut-standing portions as shown at, for example, twopositions on the front side. The guide assembly 206 is provided for thelifters 200. The guide assembly 206 is a frame-shaped member whose oneend is open. Taper-shaped lift grooves (212 and 214) and (216 and 218)which are opened on the lower side and are inclined in the obliqueupward direction are formed at two positions of each side surface. Thepins 202 and 204 provided for the lifter 200 are fitted into the liftgrooves 212 and 214, respectively. Similarly, pins at two positions onthe opposite side of the lifter 200 are fitted into the lift grooves 216and 218.

FIG. 17 is a side elevational view of an assembly state in which thelifter 200 to which the spindle motor 60 was attached is assembled tothe guide assembly 206 in FIG. 16. In the state shown in the diagram,the spindle motor 60 has descended down. In this state, when the loadingof the medium is completed, in association with the movement of the loadplate 130 from the first position to the second position, the guideassembly 206 is slid in the direction shown by an arrow 208 through alink member 205. Therefore, the pins 202 and 204 are moved upward in thedirection shown by an arrow 210 along the lift grooves 212 and 214, sothat the spindle motor 60 is lifted up, thereby enabling the spindlemotor 60 to be coupled to the hub of the medium loaded to the upperportion. Upon ejection, the guide assembly 206 is slid in the directionopposite to the arrow 208 through the link member 205. The pins 202 and204 are returned to the positions shown in the diagram along the liftgrooves 212 and 214, so that the coupling with the medium due to thelift-up of the spindle motor 60 is released.

FIG. 18 shows an assembly structure of the fixed assembly 164 providedon the inserting/ejecting port 18 side in FIG. 14 and a part of which iscut away. The ejection motor 126, gear train 134, and cam gear 140having the cam 146 for ejection are mounted on the fixed assembly 164.Further, a sensor holder 220 which is cantilever supported by a leafspring 221 is attached in close vicinity with the position of theejection motor 126. The leaf spring 221 has a U-shape. The right side ofthe leaf spring is fixed to the fixed assembly 164 and the left side isin a floating state. The sensor holder 220 is elastically supported insuch a floating portion in the vertical direction. The three pinswitches 222, 224, and 226 are arranged on the sensor holder 220. Thepin switches 222, 224, and 226 are switches which are turned on bypressures of the pins. For example, conductive rubber sheets arearranged on a pair of switch electrodes and are pressed with pins,thereby making a circuit between the electrodes conductive. Each of thepin switches 222, 224, and 226 corresponds to the carrier detecting hole44 of the CD carrier 16 shown in FIG. 4 and similarly corresponds to adetecting hole of the medium information formed in the MO cartridge 12in accordance with convex and concave portions of the ISO. Namely, whenthe detecting holes are opened on the medium side corresponding to thepin switches 222, 224, and 226, since the pin cannot be depressed, theswitch is OFF. On the other hand, when the detection hole does not existat the position corresponding to the switch pin, the pin is depressed bythe leaf spring 221, and the switch is turned on.

FIG. 19 shows contents of the medium identification in response todetection outputs of the switches when bit due to the turn-on of thethree pin switches 222, 224, and 226 is set to 1 and bit due to theturn-off is set to 0. Among them, in the CD carrier 16 in FIG. 4, sincethe carrier detecting holes 42 and 44 are formed at the positionscorresponding to the pin switches 122 and 126, the pin switches 122,124, and 126 are turned off, on, and off, respectively. Detection bitsby the three pin switches are set to "011" as shown in FIG. 20, so thatmedium ID information indicative of the CD can be obtained.

[Loading and Ejection of MO and CD]

FIGS. 20, 21, and 22 show a state from the insertion of the MO cartridge12 to the fixed assembly 115 to the completion of the loading when it isseen from the back side (lower surface side). First, FIG. 20 shows astate in which the operator inserts the MO cartridge 12 into theinserting/ejecting port 18 of the fixed assembly 115 as shown by anarrow 230. The MO cartridge 12 has a shutter 260. The shutter 260 can beopened by moving a shutter operating member 261 on the left side of thefront edge to the right side.

Position detecting holes 264 and 265 and a medium detecting hole 262 areformed in the MO cartridge 12. Among those holes, an opening position ofthe medium detecting hole 262 can be switched between the position 262and a position 262' by the slide knob. When the medium detecting hole262 is located at the position shown by a solid line, the rewritingoperation is inhibited. When the hole is located at the position 262'shown by a broken line, the writing operation can be performed. When theMO cartridge 12 is depressed as shown in the diagram, the switch knob174 of the load switch 172 provided for the load motor assembly 170 inFIG. 15 is switched to the rear side from the position shown in thediagram, so that the load motor 112 is activated. Thus, the load roller186 which has been pressed against the edge surface on the left side ofthe MO cartridge 12 is rotated counterclockwise along the load rollerguide groove 114, thereby pulling the MO cartridge 12 to the inside. Inorder to decide the slide position of the MO cartridge 12, guides 232,234, 236, and 238 made of a resin such as Teflon or the like arearranged at an interval of the lateral width W1 of the MO cartridge 12in FIG. 3. Further, a positioning knob 256 pressed by a spring 258 isarranged between the guide members 232 and 236 on the right side.Similarly, a positioning knob 252 urged by a spring 254 is provided onthe rear side of the guide 238 on the left side. By the guides 232, 234,236, and 238 and, further, the positioning knobs 256 and 252 asmentioned above, and rollers 300 and 302 the MO cartridge 12 is smoothlypulled into the fixed assembly 115 with the position held by the pull-indue to the counterclockwise rotation of the load roller 186.

FIG. 21 shows a loading state of the MO cartridge 12 due to the rotationof the load roller 186. At the start of the loading of FIG. 20, theshutter pin 104 arranged at the initial position of the guide groove 102comes into contact with the shutter operating member 261. Due to theoperation in the lateral direction along the guide groove of the shutterpin 104 in association with the pull-in of the MO cartridge 12, in astate of FIG. 21, the shutter 260 is opened up to the halfway state.When the shutter 260 is opened, a magneto-optical disk 266 and its hub268 are exposed in the opening portion 265 of the MO cartridge 12. Onthe other hand, in an initial state of FIG. 20, on the rear side of thefixed assembly 115, an arm 240 is provided so as to be rotatable aroundthe shaft 150 of the right upper corner portion as a fulcrum. A frontedge side of the arm 240 is arranged obliquely for the enclosing unit ofthe medium. A hammer-shaped MO contact portion 246 is provided as afirst contact portion at the front edge of the arm 240. When the MOcartridge 12 pulled in by the load roller 186 reaches the position shownin FIG. 21, the MO cartridge comes into contact with the MO contactportion 246, thereby clockwise rotating the arm 240 in association withthe pull-in of the MO cartridge 12 and shunting the arm. A CD contactportion 248 serving as a second contact portion is provided in themiddle of the arm 240. The CD contact portion 248 comes into contactwith the front edge of the CD carrier 16 on which the CD 14 was mounted,which will be obviously explained hereinlater, thereby likewise rotatingcounterclockwise the arm 24 and shunting it. The MO contact portion 246on the front edge side of the arm 240 is a thin portion which is dentedto the upper side for the CD contact portion 248 on the central sidewhen it is seen from the lower side. Such a thin body structure due tothe dent of the MO contact portion 246 at the front edge corresponds tothe arm escaping groove 34 of the CD carrier 16 in FIG. 4. That is, whenthe CD carrier 16 is loaded, the MO contact portion 246 enters the armescaping groove 34 formed in the CD carrier 16 in FIG. 4 due to a thinportion by the dent, so that the CD contact portion 248 provided on thecenter portion side comes into contact with the front edge surface ofthe CD carrier 16. The stopper 244 is integratedly formed on theopposite side of the rotary shaft 150 of the arm 240. As shown in FIG.11, at the initial position shown in the diagram, the stopper 244 holdsthe rear edge 131 of the side portion of the load plate 130, therebystopping the load plate 130 at the first position. When the arm 240 isrotated to the horizontal position by receiving the loading of the MOcartridge 12, the retaining of the load plate 130 by the stopper 244 isreleased, so that the load plate 130 is slid from the first position tothe second position and performs a chucking of the spindle motor.Further, the shutter pin 104 which is moved along the guide groove 102is supported to the arm 240 through a coil spring 250. At a positionserving as an inside when it is seen from the lower side of the fixedassembly 115, the bias magnet 107 is rotatably supported to the outsideby a door structure of the bias magnet holder 106 in FIG. 10. When theMO cartridge 12 is further pulled in by the load roller 186 from thestate during the loading of the MO cartridge 12 in FIG. 21, it isfinally located to the position of FIG. 22. At this position, the arm240 is rotated to the horizontal position, the retaining of the loadplate 130 by the stopper 244 is released, and the load plate 130 isinstantaneously slid by a force of the spring from the first position tothe second position. In association with it, a chucking for the hub 268of the MO cartridge 12 by the lift-up of the spindle motor is executed.

FIGS. 23, 24, and 25 sequentially show the loading state of the CDcarrier 16 on which the CD 14 was mounted to the fixed assembly 115.First, FIG. 23 shows a state in which the CD carrier 16 on which the CD14 had been mounted was inserted from the inserting/ejecting port 18 tothe fixed assembly 115 by the operator. The load roller 186 comes intocontact with the taper guide 32 of the front edge corner portion of theCD carrier 16. In this state, the load motor is activated by the turn-onof the load switch, so that the load roller 186 rotates clockwise. Theload roller 186 rotates clockwise while moving backward along the loadroller guide groove 114 and pulls in the CD carrier 16 in an interlockedmanner with the pushing operation of the operator. The CD carrier 16 ispulled along planar guides 115-1, rollers 304 and 306 and biasing spring308. The shutter pin 104 comes into contact with the taper portion of ashutter pin escaping groove 33 formed on the front edge side of the CDcarrier 16 and moves in the guide groove 102 in association with thepull-in of the CD carrier 16.

When the CD carrier 16 is pulled in to the position shown in FIG. 24,the load roller 186 rotates clockwise in a state in which it is movedbackward to the outermost position of the load roller guide groove 114,thereby pulling in the CD carrier. At this position, the MO contactportion 246 at the edge of the arm 240 is located at the edge surfaceposition of the shutter pin escaping groove 33 at the front edge of theCD carrier 16. The MO contact portion 246 is dented upward and is thin.The arm escaping groove 34 is formed in the corresponding CD carrier 16as shown in FIG. 4. Therefore, the MO contact portion 264 enters the armescaping groove 34 of the CD carrier 16 and is not pushed at thisposition by the edge of the CD carrier 16. When the CD carrier 16 isfurther pulled in, the edge of the CD carrier 16 comes into contact withthe CD contact portion 248 on the center side of the arm 240, so thatthe arm 240 rotates clockwise around the shaft 150 as a center and ismoved backward in association with the pull-in of the CD carrier 16.

Finally, as shown in FIG. 25, when the CD carrier 16 moves to theloading completion position, the arm 240 rotates to the horizontalposition by the depression by the contact of the CD carrier 16 to the CDcontact portion 248. In this state, the latch of the load plate 130 bythe stopper 244 is released. The load plate 130 is instantaneously slidto the second position by a force of the spring, thereby performing thecoupling by the lift-up of the rotary shaft of the spindle motor and themotor hub for the shaft inserting hole 66 on the lower side and thespindle side hub 62 of the CD turntable 24 to which the CD 14 mounted onthe CD carrier 16 was attached. FIG. 25 shows a comparison of theloading state of the MO cartridge 12 by an imaginary line.

[Hardware Construction]

FIGS. 26A and 26B are block diagrams showing a hardware construction ofthe optical disk apparatus of the invention. A control unit 300 in FIG.26 is installed on the printed circuit board 88 in FIG. 9 built in theoptical disk drive 10 in FIG. 1. An optical unit 302 and a drivingsystem unit 304 are provided for the control unit 300. An MPU 306 isprovided for the control unit 300. A ROM 310 and a RAM 312 are providedfor a bus 308 of the MPU 306. Control programs which are necessary forthe optical disk apparatus of the invention to operate as an MO driveand a CD player and various control parameters which are necessary forsuch a control have previously been stored in the ROM 310. The RAM 312is used as a work memory of the control operation of the MPU 306. An MOhost interface circuit 314 and a signal processing circuit 324 for MOare first provided for the bus 308 of the MPU 360 as a signal processingsystem of the MO cartridge. A buffer RAM 322 which operates as a cacheis provided for the MO host I/F circuit 314. The signal processingcircuit 324 for MO executes a writing operation or reading operation forthe loaded MO cartridge 12 on the basis of commands from an upper hostcomputer. Therefore, a write signal from the signal processing circuit324 for MO is supplied to a write amplifier 344 of the optical unit 302.A write control of a laser unit 346 is performed by the write signal ofthe write amplifier 344. A light reception signal for reproduction froma light receiving unit 348 provided for the optical unit 302 isamplified by a read amplifier 350. After that, the signal is inputted tothe signal processing circuit 324 for MO as an ID signal and an MOsignal. In the writing mode, therefore, the signal processing circuit324 for MO operates as an encoder for converting write data transferredfrom the MO host I/F circuit 314 to a write signal for the optical unit302 in accordance with a predetermined signal converting format. In thereading mode, the signal processing circuit 324 for MO operates as adecoder for demodulating the read data from the ID signal and MO signalobtained from the optical unit 302. Namely, the signal processingcircuit 324 for MO executes a read control or write control with amodulating and demodulating function of both formats of a pit positionrecording system (PPM) and a pulse width recording system (PWM), asector mark detecting function, and further, an error correctingfunction. Among them, with respect to the read signal process, an AGCamplifier which can cope with both formats of the pit position recordingsystem (PPM) and the pulse width recording system (PWM) and a PLL whichcan cope with a constant angular velocity control system (ZCAV) due to azone division are built in the circuit 324. A data clock signal and asector mark signal are demodulated from the ID signal and MO signal fromthe read amplifier 350. The pit position recording system (PPM) is asystem for recording data in correspondence to the presence or absenceof the mark. The pulse width recording system (PWM) is a system forrecording by making edge portions of the mark, namely, the front edgeand rear edge correspond to data. Theoretically, a recording density canbe doubled as compared with that of the PPM. The laser unit 346 providedfor the optical unit 302 has a single laser diode and controls a lightemission power amount in accordance with the writing mode, erasing mode,or reading mode. As a wavelength of a laser beam, for example, a shortwavelength of 680 nm is used. A CD host interface circuit 326 and asignal processing circuit 330 for CD are provided for the bus 308 of theMPU 306 as a signal processing system of the CD 14. A buffer RAM 328which operates as a cache is provided for the CD host I/F circuit 326.An audio amplifier 332 which outputs a D/A converted audio signal to anaudio terminal 309 is provided on the output side of the signalprocessing circuit 330 for CD. A read signal based on the lightreception signal of the light receiving unit 348 provided for theoptical unit 302 is inputted as a reproduction signal HF from the readamplifier 350 to the signal processing circuit 330 for CD. Therefore,the signal processing circuit 330 for CD operates as a decoder fordemodulating the reproduction signal HF derived from the optical unit302 to read data. Namely, the signal processing circuit 330 for CD has afunction to demodulate EFM data from the reproduction signal HF derivedfrom the read amplifier 350. The processing circuit 330 also has a bitclock generating function which can cope with both of the CAV controland the CLV control of the spindle motor 60 and, further, an audioreproducing function. Further, the processing circuit 330 has an errorcorrecting function with respect to each of a subcode and data whichwere demodulated as EFM data. Since the signal processing circuit 330for CD relates to only the reading operation, in the reading mode, itgenerates a read control signal to the laser unit 346, thereby allowinga read beam to be emitted by a light emission control of a laser diodefor reading.

Further, a servo control circuit 334, a spindle control circuit 336, anda motor control circuit 338 are provided for the MPU 306 as a commoncircuit unit of the MO cartridge 12 and CD 14. The servo control circuit334 drives a VCM 358 of a positioner and a lens actuator 360 which areprovided for the optical unit 302, thereby performing a seek control anda tracking control. For the seek control and the tracking control, atracking error signal TES detected by a tracking error detecting circuit(TES circuit) 352 on the basis of the light reception signal of thelight receiving unit 348 provided for the optical unit 302 is inputtedto the servo control circuit 334. A position sensor (LPOS sensor) 356for detecting the position of the lens is provided for the optical unit302 and receives the lens position detection signal LPOS. Further, theservo control circuit 334 drives a focusing actuator 362 provided forthe optical unit 302, thereby performing an automatic focusing controlof the objective lens. To perform the automatic focusing control, afocusing error signal FES detected by a focusing error detecting circuit(FES circuit) 354 on the basis of the light reception signal derivedfrom the light receiving unit 348 of the optical unit 302 is inputted.In the recording/reproducing mode by the loading of the MO cartridge 12,the tracking error detecting circuit 352 provided for the optical unit302 detects a tracking error signal according to a push-pull method. Onthe other hand, in the reproducing mode by the loading of the CD 14, thetracking error detecting circuit 352 detects a tracking error signalaccording to a heterodyne method. Ordinarily, a 3-beam system is used todetect the tracking error signal of the CD 14. In the invention,however, since the same optical unit 302 is used with respect to the MOcartridge 12 and CD 14, only one beam can be used to detect the trackingerror signal of the CD 14. On the other hand, the same push-pull methodas that of the MO cartridge 12 cannot be used because of the relationbetween a depth of pit of the CD and a wavelength of 680 nm of the laserdiode which is used. Therefore, the heterodyne method is used to detectthe tracking error signal of the CD 14. The details of the trackingerror detecting circuit 352 will be obviously described hereinlater. Thespindle control circuit 336 controls the spindle motor 60. The spindlecontrol circuit 336 controls the spindle motor 60 on the basis of aconstant angular velocity control (hereinafter, simply referred to as a"CAV control") in the recording/reproducing mode of the MO cartridge 12.On the other hand, when the CD 14 is reproduced, the spindle motor 60 iscontrolled by a constant linear velocity control (hereinafter, simplyreferred to as a "CLV control") in principle and the control mode can beswitched to the CAV control as necessary. With regard to the CLV controlof the CD, in order to improve a transfer speed for a standard speedwhich has been predetermined on the standard, for example, a times-speedcontrol such as 2-times speed, 3-times speed, 4-times speed, 6-timesspeed, and the like can be performed. In the CAV control of the MOcartridge, a speed switching for reducing a rotational speed for astandard rotational speed is executed for the improvement of a recordingdensity of the medium. The details of the spindle control circuit 336will be also clearly described hereinlater. The motor control circuit338 drives the load motor 112 and ejection motor 126 provided for thedriving system unit 304 and, further, the bias magnet 107 for applyingan external magnetic field in the writing mode and erasing mode of theMO cartridge 12. The load motor 112 is controlled on the basis of adetection signal of the load switch 172 provided for the driving systemunit 304. The detection signal of the load switch 172 is supplied to themotor control circuit 338 via a sensor adapter 342. That is, when the CD14 mounted on the CD carrier 16 or the MO cartridge 12 is inserted fromthe inserting/ejecting port, the load switch 172 is switched to a loaddetecting position at a predetermined inserting position and outputs thedetection signal. In response to it, the motor control circuit 338drives the load motor 112, thereby loading the medium. The ejectionmotor 126 receives a detection signal of the ejection switch when theejection switch knob 22 provided for an apparatus panel in FIG. 1 isdepressed and is activated and pushes and returns the load plate 130 tothe initial position as shown in FIG. 11, thereby allowing the ejectingoperation of the medium to be executed. The medium ejected by thisejecting operation results in that the load switch 172 is switched tothe reverse direction, so that the motor control circuit 338 rotates theload motor 112 in the unloading direction, thereby allowing the ejectedmedium to be fed to the inserting/ejecting port. Further, a mediumsensor 364 is provided for the driving system unit 304. Three pinswitches 222, 224, and 226 arranged on the sensor holder 220 in FIG. 18are used as a medium sensor 364. For example, three medium detectionsignals shown in FIG. 19 are generated from the medium sensor 364. Byinputting the sensor outputs to the MPU 306 via the sensor adapter 342,the medium identification contents as shown in FIG. 19 can berecognized. Further, a mode change-over switch 340 is provided for thebus 308 of the MPU 306. The mode change-over switch 340 sets a mode ofeach of the speed control system of the MO cartridge 12 and the speedcontrol system of the CD 14 in the spindle control circuit 336.Selection information of the rotational speed corresponding to the datatransfer speed is also included in the mode setting. Further, selectioninformation about the selection between the CLV control and the CAVcontrol is also included with regard to the CD 14. For example, a dipswitch or the like is used as a mode change-over switch 340. Upon set-upat the time of turn-on of a power source, the MPU 306 fetches the modeset information of the mode switch 340 and selects and sets thenecessary speed control system for the spindle control circuit 336. Inthe mode setting by the mode change-over switch 340, it can be also setby a software by a command from the upper host computer.

FIG. 27 is a flowchart for a fundamental drive processing operation inthe hardware in FIG. 26. First in step S1, the medium loading process isexecuted by waiting for the insertion of the MO cartridge 12 or the CD14 mounted on the CD carrier 16. By the medium loading process, when theloading of the MO cartridge 12 or the CD 14 mounted on the CD carrier 16to the spindle motor is completed, the set-up process in step S2 isexecuted. In the set-up process, the spindle control circuit 336 basedon the loaded medium detection information, the tracking error detectingcircuit 352 provided for the optical unit 302, and further, the signalprocessing system of the MO system or CD system provided for the controlunit 300 are set up, respectively. As a set-up, there are aninitializing process, an initialization diagnosing process, a switchingprocess according to the medium detection result, a setting process ofvarious correct and error parameters corresponding to the mediumdetection result, and the like. After completion of the set-up processin step S2, the processing routine advances to a reading/writing processin step S3. Namely, when an access command is received from the upperhost computer, the reading operation or writing operation according to acommand decoding result is executed. During the reading/writing processin step S3, the presence or absence of an ejecting operation is checkedin step S4. When the ejecting operation is discriminated, step S5follows and an ejecting process of the medium is executed.

[Host Interface]

FIG. 28 is a block diagram of a host interface between the control unit300 in FIG. 26 and the upper host computer. In the optical disk drive 10of the invention, the host I/F circuit 314 for MO and the host I/Fcircuit 326 for CD are individually provided. The host I/F circuit 314for MO and the host I/F circuit 326 for CD output interruption requestsignals El and E3 based on a command from a host computer 370 receivedto the MPU 306, execute signal processes for MO or CD in FIG. 26 andvarious controls under the control of the MPU, return the results asresponse signals E2 and E4 to the host I/F circuits 314 and 326, andperform a necessary response to the host computer 370. In the opticaldisk drive 10 of the invention, by individually providing the host I/Fcircuit 314 for MO and the host I/F circuit 326 for CD, the hostcomputer 370 is allowed to recognize the existence of two devices by thehost interface which is connected to the host computer 370 via a cable373. Therefore, different ID numbers which are used for the hostinterfaces have been preset for the host I/F circuit 314 for MO and thehost I/F circuit 326 for CD, respectively. For example, when an ATAPI(AT attachment packet interface) as one of the standards of theperipheral device interface is used as a host interface, a master is setinto the host I/F circuit 314 for MO as an ID number and a slave is setinto the host I/F circuit 326 for CD. When a fast SCSI-2 is used as ahost interface, it is sufficient to set two device numbers among thedevice numbers #0 to #7 into the host I/F circuit 314 for MO and thehost I/F circuit 326 for CD. For the two host I/F circuits 314 and 326of the optical disk drive 10 of the invention having the individual IDnumbers, on the host computer 370 side, ordinarily, two drivers of adevice driver 366 for MO and a device driver 368 for CD exist dependingon a device control software (DIOS) under the domination of an OS 371.For the two device drivers 366 and 368 of the host computer 370,although the optical disk drive 10 of the invention is physically onedevice, it can be allocated as two independent devices in the hostinterface. Therefore, although the optical disk drive 10 of theinvention can access the MO cartridge 12 and CD 14 by using the samemechanism, the host computer 370 can request an input and an output onthe assumption that both of the disk driver for MO and the CD playereffectively exist without being aware of a physical single constructionof the optical disk drive 10.

A flowchart of FIG. 29 shows processes for a host command interruptionof the MPU 306 when using the ATAPI as a host interface of FIG. 28 andrelates to the case where the host I/F circuit 314 for MO is set to amaster and the host I/F circuit 326 for CD is set to a slave. In case ofthe ATAPI, the master and slave can be set by an external switchprovided for the interface circuit. It is now assumed that the hostcomputer 370 designates "ID=master" for an input/output request to theMO drive and generates a host command. Although the host command isreceived by each of the host I/F circuit 314 for MO and the host I/Fcircuit 326 for CD, the host I/F circuit 314 for MO in which (ID=master)was set recognizes that the command is a host command to itself from anID parameter in the command, and generates the interruption signal E1 tothe MPU 306. The MPU 306 checks the interruption in step S1. Whenreceiving the interruption from the MO side, step S2 follows and a checkis made to see if the ID number of the host I/F circuit 314 for MOindicates the master. In this instance, since the host I/F circuit 314for MO has been set to the master, step S3 follows. A master responseflag to perform a response to the host command from the host I/F circuit314 for MO is set. Subsequently, the MPU 306 advances to step S5 andchecks to see if the MO cartridge has been inserted. If YES, an MO readyis set in step S6. In step S8, the MO controller is activated and aresponse process for recording or reproduction is executed. When the MOcartridge is not inserted, an MO not ready is set in step S7. The MO notready is returned as an MO controller response in step S8. When the hostcomputer 370 generates a host command which designates "ID=slave" forthe input/output request to the CD player, the host I/F circuit 326 forCD recognizes that the command is a host command to itself, so that itgenerates an interruption signal E2 to the MPU 306. Therefore, whenreceiving the interruption from the CD side in step S1, the MPU 306progresses to step S9 and checks to see if the ID number of the host I/Fcircuit 326 for CD indicates the slave. The processing routine advancesto step S11 and a slave response flag to perform a response to the hostcommand from the host I/F circuit 326 for CD is set. When the CD carrieris inserted in step S12, a CD ready is set in step S13. In step S15, aCD controller is activated and a response process for reproduction isexecuted. When the CD carrier is not inserted, an CD not ready is set instep S14. In step S15, a CD not ready is returned as a CD controllerresponse.

[Tracking Error Detecting Process]

FIG. 30 is a block diagram of the tracking error detecting circuit 352in FIG. 26. A reflected light of a laser beam for the optical disk ofthe MO cartridge 12 or the CD 14 mounted on the CD carrier 16 is formedas an image onto a 4-split photodetector 372. Therefore, the 4-splitphotodetector 372 generates light reception signals Ea, Eb, Ec, and Edin correspondence to the dividing positions, respectively. A trackingerror detecting circuit 374 for MO and a tracking error detectingcircuit 376 for CD are individually provided for the 4-splitphotodetector 372. The tracking error detecting circuit 374 for MOdetects a tracking error detection signal TES1 by the push-pull method.The tracking error detecting circuit 376 for CD detects a tracking errorsignal TES2 by the heterodyne method. Either one of the detectionsignals TES1 and TES2 of the tracking error detecting circuits 374 and376 is selected by a multiplexer 378 and is outputted as a trackingerror signal TES. The multiplexer 378 selects an output of the trackingerror detecting circuit 374 for MO upon recording and reproduction ofthe MO cartridge 12 and selects an output of the tracking errordetecting circuit 376 for CD upon reproduction of the CD 14 by aswitching signal from the MPU 306. Further, the switching signal fromthe MPU 306 is inputted to the tracking error detecting circuit 376 forCD, thereby switching a low band cut-off frequency of a high pass filterprovided for the tracking error detecting circuit 376 for CD inaccordance with a seeking speed.

The reason why the heterodyne method is used for the tracking errordetecting circuit 376 for CD will now be described. Ordinarily, thetracking error detecting circuit for CD uses a 3-beam system. In theoptical disk drive of the invention, however, the recording andreproduction of the magneto-optical disk of the MO cartridge 12 and theCD 14 have to be performed by using the common optical system. In thedetection of the tracking error of the MO cartridge 12, one beam by thepush-pull method is used and the ordinary 3-beam system in the CD cannotbe used. Therefore, it is sufficient to use the same push-pull method ofone beam as that for the MO cartridge for the tracking error detectionfor CD. In this case, with respect to the conventional laser beam of awavelength 780 nm of a low recording density, since a depth of pit ofthe CD is equal to or less than λ/4, the tracking error by the push-pullmethod can be detected. In the embodiment of the invention, however, alaser beam of a short wavelength of 680 nm is used in order to raise arecording density. In the laser beam of the wavelength of 680 nm, a pitdepth of CD is equal to or larger than λ/4. According to the push-pullmethod whereby the tracking error signal is detected from a differencebetween the two light reception signals derived from a 2-splitphotodetector, the tracking error signal is lost and cannot be detected.According to the invention, therefore, the heterodyne method whereby thetracking error signal can be detected even in case of the wavelength of680 nm irrespective of the pit depth is used.

FIG. 31 is a block diagram of the tracking error detecting circuit 376for CD using the heterodyne method of FIG. 30. In the block diagram,with respect to the four light reception signals Ea, Ec, Eb, and Ed fromthe 4-split photodetector 372, addition signals (Ea+Ec) and (Eb+Ed) areobtained by adders 380 and 382. Subsequently, two heterodyne signals areobtained as [(Eb+Ed)-(Ea+Ec)] and [(Ea+Ec)-(Eb+Ed)] by adders 384 and386. Further, an addition signal (Ea +Eb+Ec+Ed) of four signals isobtained by an adder 388. An addition signal HF of the adder 388 is asignal which changes like a sine wave when a beam spot transverses a pittrain of CD and causes an envelope change such that an amplitude issmall at a pit edge and is maximum at a pit center and decreases at thepit edge. On the other hand, a heterodyne signal HTD1 which is obtainedby the adder 384 is a signal whose phase is shifted by 90° for the phaseof the addition signal HF and its amplitude changes such that it isequal to 0 at a pit center and is maximum between pits. A heterodynesignal HTD2 of the adder 386 is a signal obtained by inverting the phaseof the heterodyne signal HTD1 of the adder 384. From the addition signalHF from the adder 388, low band components of a predetermined low bandcut-off frequency or lower are eliminated by a high pass filter 390.After that, the signal HF is inputted to a comparator 392 and a peakholding circuit 397. The comparator 392 operates as a zero-crosscomparator, detects a zero-cross timing of the addition signal HF fromthe adder 388, and outputs a sampling pulse to a peak holding circuit394. Each time the sampling pulse is obtained by the zero-crossdetection of the comparator 392, the peak holding circuit 394 samplesand holds the two heterodyne signals HTD1 and HTD2 outputted from theadders 384 and 386 at a peak timing of the sine wave and individuallyoutputs. The heterodyne signal HTD2 is a signal whose phase is invertedby 180° for the phase of the heterodyne signal HTD1. When the holdinglevel of the heterodyne signal HTD1 at the sampling timing is at the (+)level, the holding level of the heterodyne signal HTD2 is at the (-)level. The holding circuit 394, therefore, inverts the polarity of theholding signal of the heterodyne signal HTD2 and outputs the invertedsignal to a selecting circuit 396. The selecting circuit 396 forms atracking error signal by alternately switching the two holding signalsfrom the holding circuit 394 at a sampling timing in association withthe zero-cross detection of the addition signal HF by the comparator392. The tracking error signal from the selecting circuit 396 is sent toan AGC circuit 398 and is subjected to a correction by a gain settingsuch that the peak level at the pit center of the addition signal HFobtained from the peak holding circuit 397 at that time is set to apredetermined standardized level. The resultant corrected signal isoutputted as a tracking error signal TES2 for CD detected by theheterodyne method. The low band cut-off frequency of the high passfilter 390 is switched by a switching signal from the MPU. The switchingsignal switches the low band cut-off frequency in accordance with theseeking speed of the pickup. Namely, upon low speed seek by the movementof the carriage 118 in the mechanism unit 101 in FIG. 12 by the VCM 358in FIG. 26, the lower low band cut-off frequency according to thefrequency of the tracking error signal TES2 for CD which is obtained bythe low speed seek is set. On the contrary, upon high speed seek, thehigh pass filter 390 is switched to a higher low band cut-off frequencydepending on the high seeking speed by the switching signal.

FIG. 32A shows a tracking error signal 412 which is obtained by theheterodyne method in FIG. 31 by the low speed seek. On the other hand,for example, when the seeking speed is changed to a high speed of thedouble speed, a tracking error signal 414 in FIG. 32B is obtained. Whenthe seeking speed is changed to the high speed as mentioned above, thefrequency of the addition signal HF from the adder 388 in FIG. 31 whichis used to form the tracking error signal increases. When the low bandcut-off frequency at the time of the low speed seek is used, the lowband components are not sufficiently cut and the zero-cross timingcannot be accurately detected. Upon high speed seek, the low bandcut-off frequency of the high pass filter 390 is raised and the low bandcomponents are sufficiently eliminated so that the sine wave frequencyaccording to the high speed seek can be accurately reconstructed. Thezero-cross timing is certainly detected, thereby enabling the trackingerror signal to be accurately formed.

FIG. 33 is a block diagram of the tracking error detecting circuit 374for MO in FIG. 30. In the tracking error detecting circuit 374 for MOusing the push-pull method, four light reception signals from the4-split photodetector 372 are converted into the light receptioncorrespondence signals (Ea+Ed) and (Eb+Ec) of the 2-split photodetectorby adders 400 and 402. A tracking error signal is formed by an adder 404as a difference [(Ea+Ed)-(Eb+Ec)] between those light receptioncorrespondence signals. An addition signal (Ea+Eb+Ed+Ec) is obtained byan adder 406 and its peak level is detected by a peak holding circuit408 and supplied to an AGC circuit 410. A gain to adjust the peakholding value to a preset standardized level is obtained. The trackingerror signal derived from the adder 404 is corrected by the gain and theresultant corrected signal is outputted as a tracking error signal TES1for MO. In the embodiment of the invention, since the use wavelength ofthe laser diode is equal to 680 nm, the heterodyne method is used todetect the tracking error signal for CD. However, when the usewavelength of the laser beam is equal to 780 nm, the pit depth of CD isequal to or less than λ/4 and the tracking error detection signal by thepush-pull method can be detected. In this case, with respect to thetracking error detecting circuit for CD, it is also sufficient toconstruct so as to detect the tracking error by the push-pull method.

[Set-up and Spindle Control]

(1) CAV control and CLV control

FIG. 34 is a block diagram of the spindle control circuit 336 in FIG.26. The spindle control circuit realizes the CAV control which is usedfor recording and reproduction of the MO cartridge 12 and the CLVcontrol which is used upon reproduction of the CD 14. Further, uponreproduction of the CD 14, the spindle control circuit enables theswitching between the CLV control and the CAV control. In FIG. 34, aclock generator 416, a programmable frequency divider 418, a register420 for setting a frequency dividing ratio of the programmable frequencydivider 418, and a CAV error detecting circuit 422 to perform the CAVcontrol are first provided. The clock generator 416 generates a clockpulse of a predetermined reference frequency. The frequency dividingratio is set into the programmable frequency divider 418 by the register420 and the frequency divider 418 outputs a target clock pulse whichgives a target rotational speed of a frequency obtained by dividing theclock frequency in accordance with the frequency dividing ratio to theCAV error detecting circuit 422. As for the target frequency clock whichgives the target speed by the programmable frequency divider 418, theset frequency dividing ratio is changed by an instruction from the MPU306 in accordance with a spindle rotational speed of the CAV controlwhich is determined by a recording density of the medium. A rotationdetection pulse from a pulse generator 430 provided for the spindlemotor 60 is inputted to the CAV error detecting circuit 422. In place ofthe pulse generator 430, a rotational speed can be also detected from aHall element or a counter electromotive force of a motor. The CAV errordetecting circuit 422 detects a phase difference between the targetfrequency clock (reference speed clock) from the programmable frequencydivider 418 and the rotation detection pulse from the pulse generator430 as an error. The error signal is supplied to a filter circuit 436through a multiplexer 434 and is subjected to a predetermined gaincontrol by a gain control circuit 438. After that, a current accordingto the error is supplied to the spindle motor 60 by a driver 440,thereby performing the CAV control. On the other hand, a spindle controlcircuit 424 for CD and a register 426 for designating a times-speed areprovided for the CLV control. The spindle control circuit 424 for CDcompares a frame sync signal of CD demodulated by the optical unit 302and signal processing circuit (CD decoder) 330 for CD with a referenceframe sync signal obtained by frequency dividing a fundamental clock inaccordance with the times-speed designation of the register 426, therebydetecting a phase difference. The current according to the error issupplied to the spindle motor 60 by the multiplexer 434, filter circuit436, gain control circuit 438, and driver 440, thereby performing theCLV control. In case of the standard speed designation, a frequency ofthe frame sync signal that is demodulated from the CD is equal to 7.35kHz. The spindle control circuit 424 for CD accelerates or deceleratesthe spindle motor 60 in accordance with the track position.

FIG. 35A shows characteristics of the target speed of the spindle motor60 for the track position in the CLV control. In order to make thelinear velocity on the medium constant irrespective of the trackposition, linear characteristics such that the linear velocity is set toa highest velocity VH on the inner side and to a lowest velocity VL onthe outer side are set and, in accordance with the track position, thespindle motor is controlled so as to obtain a rotational speed accordingto the linear characteristics. For example, when the standard speed isdesignated, the velocity is linearly changed so that the rotationalspeed is set to 500 r.p.m. for the innermost track and to 200 r.p.m. forthe outermost track. Therefore, when the double speed is designated bythe register 426, the rotational speed is set to 1000 r.p.m. for theinnermost track and to 400 r.p.m. for the outermost track. When the4-times speed is designated, the rotational speed is set to 2000 r.p.m.at the innermost track and to 800 r.p.m. at the outermost track.Further, when the 6-times speed is designated, the rotational speed isset to 3000 r.p.m. for the innermost track and to 1200 r.p.m. for theoutermost track. According to the invention, with respect to the CD 14on which pits were recorded for such a CLV control as a prerequisite,the CAV control is applied for a high speed data transfer. When the CAVcontrol is executed with regard to the CD 14 on which the pits wererecorded for the CLV control as a prerequisite, the reproducing andrecording frequency differs depending on the track position. Namely, thepits are recorded on the CD 14 at a constant linear density irrespectiveof the track position. When the CD 14 is reproduced by the CAV control,namely, at a constant angular velocity rotation, since the reproducingfrequency depends on a peripheral speed of the track position, thereproducing frequency is low on the inner side and is high on the outerside. Therefore, when the CD 14 is reproduced by the spindle control bythe CAV control, as shown in FIG. 35B, a clock generation such that aread clock frequency is linearly increased from a lowest clock frequencyf_(L) to a highest clock frequency f_(H) for a change from the innerside to the outer side of the track position has to be performed. Such afunction for varying the clock frequency in accordance with the trackposition which can cope with the CLV control is realized by the CLVcontrol of the signal processing circuit 330 for CD provided for thecontrol unit 300 in FIG. 26 and a bit clock generating function whichcan cope with the CLV control.

FIG. 36 shows the CAV control and CLV control as a spindle speed controlwith respect to two kinds of media MO and CD and, further, modes 1 to 8which can be set by the mode change-over switch 340 in FIG. 26 withrespect to the speed in each medium, respectively. Modes 1 to 3 relateto the MO cartridge 12 as a target, codes 111 to 101 are used, and theCAV control is used as a spindle speed control. In case of the medium of90 mm--MO in modes 1 to 3, recording densities are different and arehigher in accordance with the order of modes 1, 2, and 3. The MO mediumin mode 1 is an existing medium of a recording capacity of 128 MB, 230MB, 540 MB, or 640 MB and its rotational speed N1 is set to, forexample, a standard rotational speed N1=3600 r.p.m. Mode 2 relates to anMO medium of a recording capacity of, for example, 1 GB. Since therecording density is high, in case of the standard rotational speedN1=3600 r.p.m., since a signal recording and reproducing frequency onthe outer side is too high and exceeds an encoding and decoding ability,the rotational speed is reduced to N2=2400 r.p.m.

Mode 3 relates to an MO medium of a recording capacity of, for example,4.3 GB and the rotational speed is reduced to N3=1800 r.p.m. Modes 4 to7 relate to 120 mm--CD in the CD 14 which is mounted onto the CD carrier16 and is loaded. Mode 4 relates to a code 100 and the CAV control isexecuted as a spindle control. A rotational speed N4 in this case is setto an average conversion value of a 4-times speed of the CLV control.For example, since the 4-times speed of the CLV control of the CD isequal to 2000 r.p.m. at the innermost track and to 800 r.p.m. at theoutermost track, N4=1400 r.p.m. is used as an average conversion value.Modes 5 to 7 relate to the CLV control with respect to the 120 mm--CDand the 6-times speed, 4-times speed, or standard speed is applied as arotational speed. Last mode 8 relates to the 80 mm--CD as a target, theCLV control is used as a spindle control, and the rotational speed isset to the standard speed. The MPU 306 in FIG. 26 identifies the mediumin accordance with FIG. 19 from the sensor signal of three bits which isderived from the medium sensor 364 through the sensor adapter 342 whenthe loading of the medium is finished. On the basis of the specifiedmode set by the mode change-over switch 340, the switching between theCAV control and the CLV control and the setting of the standard speed oran arbitrary-times speed as a rotational speed are performed for thespindle control circuit 336 with reference to the contents of FIG. 36.The setting by the mode change-over switch 340 is executed one mode byone with respect to each of the MO cartridge 12 in modes 1 to 3 and theCD 14 in modes 4 to 8.

Referring again to the spindle control circuit in FIG. 34, in accordancewith the designated mode in FIG. 35, switching information indicative ofeither one of the CAV control and the CLV control corresponding to themedium loaded at that time has been set in a register 442. Therefore,the multiplexer 434 selects either one of outputs of the CAV errordetecting circuit 422 and spindle control circuit 424 for CD inaccordance with the selection information of CAV or CLV in the register442 and establishes a control loop of the selected speed control system.Further, the filter circuit 436 and gain control circuit 438 can set afilter constant and a gain from the outside and are controlled bysimilarly receiving the setting of the optimum filter constant andoptimum gain by the MPU for the register 442. For example, as shown inFIG. 37, with respect to the CAV control, the filter constants and gainshave been prepared for modes 1 to 4. When the MO cartridge 12 isrecognized by the medium identification, the filter constant and gaincorresponding to the mode number set at that time are set into theregister 442. The filter circuit 436 is controlled to the optimum filterconstant and the gain control circuit 438 is controlled to the optimumgain. Further, in FIG. 37, as for the frequency dividing ratio forallowing the programmable frequency divider 418 to generate the targetfrequency clock of the CAV control, values DV1, DV2, DV3, and DV4corresponding to the rotational speeds N1, N2, N3, and N4 in FIG. 36have been stored. FIG. 38 shows filter constants and gains with respectto modes 5 to 8 for the CLV control as a target and times-speeddesignation in the CLV control has also been stored together.

(2) Automatic Switching by Medium Detection

A set-up process until the access from the host computer side is enabledafter completion of the medium loading in the optical disk drive 10 ofthe invention will now be described. FIG. 39 is a fundamental flowchartfor the set-up process in the optical disk drive of the invention. Instep S1, when the loading of the MO cartridge 12 or the CD 14 mounted onthe CD carrier 16 is completed, the detection information of the mediumsensor 364 is read in step S2. On the basis of the medium sensorinformation which was read, a check is fundamentally made to see if theinserted medium is the MO cartridge 12 or CD 14 with reference to thecontrol information in FIG. 19. In case of the MO cartridge, step S4follows and the spindle control is set up. In the set-up of the spindlecontrol, the CAV control and the standard or arbitrary-times speed areset. In step S5, the optical system is set up. In the set-up of theoptical system, since the medium is the MO, the tracking error detectingcircuit is switched to the tracking error detecting circuit for MO. Instep S6, the MO signal processing system is set up. On the other hand,when the medium is judged to be the CD in step S3, step S7 follows. Thespindle control for the CD as a target is set up. Upon set-up, the CAVcontrol or CLV control is selected in accordance with the designatedmode at that time. With respect to the CLV control, a plurality oftarget speeds, namely, the standard speed and the arbitrary-times speedare selected. In step S8, the optical system is set up. In the set-up ofthe optical system, the tracking error detecting circuit is switched tothe tracking error detecting circuit for CD using the heterodyne method.In step S9, the CD signal processing system is set up.

FIG. 40 shows a set-up of the spindle control for the MO cartridge 12shown in step S4 in FIG. 39 as a target. First in step S1, the presentset mode is recognized. The set mode for MO as a target is any one ofmodes 1 to 3 in FIG. 36. Since all of modes 1 to 3 relate to the CAVcontrol in this case, the switching to the CAV control is executed instep S2. Specifically speaking, the multiplexer 434 in FIG. 36 isswitched to the CAV error detecting circuit 422 side. In step S3, thefrequency dividing ratio to obtain the rotational speed that is decidedin the mode at that time is set into the programmable frequency divider418. A frequency of the target frequency clock for the CAV errordetecting circuit 422 is set. In step S4, the optimum filter constantcorresponding to the designated mode at that time is set into the filtercircuit 436. In step S5, the optimum gain is set into the gain controlcircuit 438. After completion of the setting and switching of thosecontrol parameters, the spindle motor 60 is activated in step S6. Whenthe rotational speed of the spindle motor reaches a target speed in stepS7, the processing routine is returned to the main routine in FIG. 39.

FIG. 41 shows the set-up process of the spindle control with respect tothe CD in step S7 in FIG. 39. The present mode is recognized in step S1.As for the CD, any one of modes 4 to 8 in FIG. 36 has been set. In stepS2, a check is made to see if the control mode is the CLV control. Incase of any one of modes 5 to 8, since the CLV control is executed, theprocessing routine advances to step S3. The multiplexer 434 in FIG. 34is switched to the CLV error detecting circuit 428 side. A target speedinitial value at the outermost track in which the positioner is locatedat present is set into the spindle control circuit 424 for CD via theregister 426. In step S7, the optimum filter constant is set. In stepS8, the optimum gain is set. After that, in step S9, the spindle motoris activated. In step S10, when the arrival at the target speed isdiscriminated, the processing routine is returned to the main routine inFIG. 39. On the other hand, when the present set mode is mode 4 in FIG.36 and the CAV control has been set in step S2, the processing routineadvances to step S5. The multiplexer 434 is switched to the CAV errordetecting circuit 422 side. In step S6, the frequency dividing ratio toobtain the target frequency clock at the outermost position where thepositioner is located at present is set into the programmable frequencydivider 418 via the register 420. In a manner similar to the above, theoptimum filter constant in the CLV control is set in step S7. Theoptimum gain by the CLV control is set in step S8. After that, thespindle motor is activated in step S9. When the rotational speed of thespindle motor reaches the target speed in step S10, the processingroutine is returned to the main routine in FIG. 39.

(3) Cache Set-up of CD Host I/F

FIG. 42 shows a process which is peculiar in the set-up of the CD signalprocessing system in step S9 in FIG. 39. In the CD processing system ofthe control unit 300 in FIG. 26, the buffer RAM 328 which operates as acache is provided for the host I/F circuit 326 for CD. In the ordinarycaching, after completion of the set-up, the data provided by a commandfrom the host computer is decoded and the requested data is responded.In this case, the cache cannot be used and a time until the data isfirst requested after the CD 14 was loaded becomes vain. In addition,since the motor is activated in a stopping state of the spindle motorand an access is enabled, it takes a surplus time for data access. Inthe invention, therefore, a waiting time for an initializing processafter the CD 14 was loaded is effectively used and in order to promptlyaccess the data which is requested first after the CD 14 was inserted,since the data which is requested first from the host computer at thetime of the set-up process for initialization of the drive haspreviously been known with respect to the CD 14, the data that isrequested is staged into the buffer RAM 328 at the time of the set-upprocess, thereby raising a hit ratio of the first data access after theCD 14 was inserted. Generally, the file access from the host computer tothe CD signal processing system is executed by the following procedure.

I. A disk label specified in absolute address 00; 02; 16 is read out.

II. An address in a bus table is obtained from the disk label.

III. An address of the file is examined from the bus table and theaddress is sought.

Namely, in order to obtain the information of the loaded CD 14, first,the reading of the disk label and the detection of the address of thebus table are certainly required. Therefore, at the time of the set-upof the optical disk drive, those data is staged into the buffer RAM 328.Namely, as shown in the flowchart of FIG. 42, as a routine for set-up ofthe CD signal processing system, an initialization diagnosing process ofthe signal processing circuit 330 for CD, namely, the decoder and thehost I/F circuit 326 for CD is executed in step S1. After completion ofthe initialization diagnosing process, the apparatus seeks to theabsolute address 00; 02; 16 of the CD 14 and the disk label is read outand is staged into the buffer RAM for cache in step S2. In step S3, theaddress of the bus table of the disk is obtained from the staged disklabel information and the information of the bus table is also stagedinto the buffer RAM 328. Therefore, with respect to each request of thereading of the disk label and the address of the bus table which areexecuted first from the host computer after the set-up process wasfinished, the CD host I/F circuit 326 causes a cache hit with respect toeach buffer RAM 328 and can immediately respond to the host computerwithout needing the CD access. The processing time until the start ofthe file access after the CD 14 was inserted can be remarkably reduced.

(4) Error Recovery

FIG. 43 is a flowchart for a recovery process for a read error when theCD 14 is inserted. In the optical disk drive of the invention, in orderto also raise a data transfer speed with respect to the CD 14, forexample, in mode 5 in FIG. 36, the high speed spindle control of thespeed that is six times as high as the standard speed is executed.However, a process for raising the rotational speed of the CD 14 to thehigh speed such as a 6-times speed in order to raise the transfer speedbecomes a severe condition for the CD 14 which has been standardized onthe assumption that the disk is inherently rotated at a low speed forreproduction of music pieces as a prerequisite. Therefore, a propercountermeasure is needed when a data read error occurs. That is, inorder to raise the data transfer speed by rotating the CD 14 at a highspeed, a frequency of a read clock is raised in correspondence to anincrease in rotational speed. However, even if only such acountermeasure is taken, the apparatus cannot cope with a read error dueto an eccentricity of the disk or the like. When the CD is rotated at aspeed that is a few times as high as the standard speed, in many cases,noises are multiplexed to the signal from the pickup. According to theinvention, therefore, the CD 14 is rotated at a high speed such as a4-times speed and if a read error occurs during the reproduction, therotational speed of the spindle motor is switched to a low speed and aretry is performed, thereby performing an error recovery. When therotational speed is switched to a low speed for the read error duringthe high speed rotation, a tracking ability of the pickup for aneccentricity of the CD is improved, an amount of noises which are mixedis also reduced, and the read signal also becomes stable. Therefore, thedata can be read out at the occurring position of the read error and theread error can be recovered by the retry.

Further, in the flowchart of FIG. 43, with respect to the CD 14 of theinvention, when mode 4 is designated, the rotational speed is set to the4-times speed based on the CAV control. Since the CD 14 has inherentlybeen standardized on the assumption that the disk is accessed by the CLVcontrol for music reproduction as a prerequisite. In case of the CAVcontrol by the 4-times speed, such a high speed becomes a severecondition and a read error similarly occurs. When a read error occurs bysuch a 4-times speed of the CAV control, by switching the control modeto the CLV control as an inherent control of the CD 14 and retrying, theerror recovery is performed. In the CD reading process of FIG. 43, firstin step S1, the seek control for the track address designated by acommand from the host computer is executed. When the completion of theseek control is discriminated in step S2, the processing routineadvances to an on-track control in step S3. The reading operation isstarted in step S4. If an error is discriminated during the readingoperation in step S5, a check is made in step S6 to see if the retry hasbeen performed a specified number of times. If NO, a count value of aretry counter (N) is increased by "1" in step S7. After that, thereading operation is repeated in step S4. If the error cannot berecovered even after the retry was performed the specified number oftimes, step S8 follows and a check is made to see if the control mode isat present the CAV control. If YES, step S9 follows and the control modeis switched to the CLV control. The reading operation is again executedin step S4. When the control mode is switched from the CAV control tothe CLV control, since it is the control mode that is inherent to theCD, the read error occurred is recovered and the processing routine isnormally finished. In step S8, when the control mode is the CLV controlat present instead of the CAV control, a check is made in step S10 tosee if the rotational speed is the lowest speed, namely, the standardspeed. If NO, the rotational speed is switched to the low speed in stepS11. After that, the reading operation is again executed in step S4. Byswitching the rotational speed to the low speed, a tracking ability ofthe pickup for the eccentricity of the disk is improved and the readsignal is also stabilized, so that the read error is recovered and theprocessing routine is normally finished. On the other hand, in step S9,if the read error cannot be recovered even by switching from the CAVcontrol to the CLV control, by performing a retry process in which therotational speed is switched to the low speed with respect to the CLVcontrol in steps S10 and S11, the read error can be certainly recovered.FIG. 43 shows the reading process of the CD 14 as an example. However,with respect to the MO cartridge 12 as well, as shown in FIG. 35, sincethe standard speed, 2-times speed, and 3-times speed are set, forexample, when a read error occurs with respect to the 2-times speed and3-times speed in modes 2 and 3, it is also possible to recover the errorby executing the retry process such that the rotational speed isswitched to the low speed side and the reading operation is againperformed.

(5) CLV/CAV Switching According to Track Position of CD

FIG. 44 is a characteristics diagram of a speed control switching forperforming the CLV control on the inner rim side of the CD andperforming the CAV control on the outer rim side with regard to thespeed control of the spindle motor when the CD is loaded. As shown inFIG. 36, the optical disk driver of the invention can control therotational speed in correspondence to the 6-times speed, 4-times speed,and standard speed like modes 5 to 7 with respect to the CD and can copewith the improvement of the data reading speed. In mode 4, the CAVcontrol at the 4-times speed can be executed. In case of operating theCD by the CAV control, how to decide the rotational speed is important.

In FIG. 44, first, characteristics 500 show the standard rotationalspeed for the track position when the CD is CLV controlled. Since thelinear density of the CD in the track direction is constant irrespectiveof the track position, the rotational speed of the spindle motor is highon the inner side and is low on the outer side. Now, assuming that thestandard rotational speed of an outermost track T0 is set to 200 r.p.m.,the standard rotational speed of an innermost track T2 is equal to 500r.p.m. Now, assuming that the signal processing circuit (decoder) 330for CD which is used for the control unit 300 in FIG. 26 can cope withup to a speed that is four times as high as the speed shown by thecharacteristics 500 of the standard rotational speed, the 4-timesrotational speed of the outermost track T0 is equal to 800 r.p.m.Therefore, in the CAV control of the speed that is four times as high asthe normal speed of the CD, it is sufficient to set the rotational speedto 800 r.p.m. However, according to the CD recorded on the basis of theCLV control as a prerequisite, the standard rotational speed for theinnermost track T2 according to the characteristics 500 is inherentlyequal to 500 r.p.m. In case of the CAV control of 800 r.p.m., only thereading speed of 1.6 times (=800 r.p.m./500 r.p.m.) can be obtained inthe innermost track T2. In case of such a times speed, the drive cannotbe regarded as a high speed drive. As shown in FIG. 44, therefore, theinvention is characterized in that the apparatus is operated by the CLVcontrol in a region on the inner rim side where the reading speed isrelatively slow in the CAV control. In FIG. 44, an intermediate track T1between the outermost track T0 and the innermost track T2 is set to aswitching point. The rotational speed in the characteristics 500 of thetrack T1 at the switching point is equal to 350 r.p.m. On the outer sidethan the switching track T1, the rotational speed 800 r.p.m. of the CAVcontrol is set as shown by characteristics 502. On the inner side thanthe switching track T1, the CLV control according to characteristics 504in which the speed is four times as high as that of the standardcharacteristics 500 is executed. Thus, the CLV control of the 4-timesspeed according to the characteristics 504 is executed on the inner sidethan the switching track T1 and the CAV control of 800 r.p.m. of thecharacteristics 502 is executed on the outer side than the switchingtrack T1. Since the standard rotational speed in the switching track T1is equal to 350 r.p.m., a reading speed of 2.3 times (=800 r.p.m./350r.p.m.) or more can be assured in the region on the outer side of thetrack T1. The switching track t1 can be set to an arbitrary trackbetween the outermost track and the innermost track as necessary. Forexample, assuming that the track of the standard rotational speed 300r.p.m. of the characteristics 500 is set to the switching track in thiscase, a reading speed of 2.6 times (=800 r.p.m./300 r.p.m.) or more canbe assured in the region of the outer side than the switching track.

FIG. 45 is a flowchart for a switching process between the CLV controland the CAV control according to the track position in FIG. 44. First,when a command interruption is performed by executing the command of thereading or writing request from the host computer, the CAV/CLV switchingcontrol is activated. In step S1, a track address given by the commandis read. In step S2, a check is made to see if the designated trackaddress is located on the inner side than the address of the switchingtrack t1 in FIG. 44. If YES, step S3 follows and the CLV control of the4-times speed is performed. When the designated track address is locatedon the outer side, step S4 follows and the CAV control of, for example,800 r.p.m. is executed. By such a switching between the CLV control onthe inner side of the CD and the CAV control on the outer side, areduction in reading speed in the region on the inner side in which thelinear velocity is slower as compared with that when the CAV control isperformed for the whole region can be prevented. With respect to theouter side in which the linear velocity by the CAV control rises, bysetting the CAV control, the acceleration and deceleration of thespindle motor according to the track position is unnecessary. There isan advantage such that the electric power consumption can be reduced.

(6) Switching Between CAV on the Inner Rim Side and CLV on the Outer RimSide of CD

FIG. 46 shows a procedure to decide the rotational speed when the CD isloaded and the spindle motor is CAV controlled. First, when the standardspeed of the CD is designated, as shown in standard CLV characteristics510, in order to always obtain a constant linear velocity even at anyone of the inner and outer track positions, the spindle rotational speedis set to a high speed on the inner side and as a track positionapproaches the outer side, the spindle rotational speed is linearlyreduced. In case of the standard CLV characteristics 510, the spindlerotational speed is set to 500 r.p.m. at the position of the innermosttrack T2 and is set to 200 r.p.m. at the outermost track position T0.For such standard CLV characteristics 510, for example, when the 4-timesspeed is designated, CLV characteristics 512 of the 4-times speed areobtained. In the 4-times speed CLV characteristics 512, the rotationalspeed in the innermost track T2 increases from the standard speed of 500r.p.m. to the 4-times speed of 2000 r.p.m. Similarly, the rotationalspeed in the outermost track T0 increases from the standard speed of 200r.p.m. to the 4-times speed of 800 r.p.m. To satisfy such 4-times speedCLV characteristics 512, the CD decoder, namely, the signal processingcircuit 330 for CD in FIG. 27 has an ability which can cope with thesignal frequency that is read in accordance with the spindle rotationalspeed by the 4-times speed CLV characteristics 512. With regard to the4-times speed CLV characteristics 512, in order to set the CAV control,it is now assumed that the rotational speed 2000 r.p.m. of the 4-timesspeed CLV characteristics 512 of the innermost track T2 is set to theconstant rotational speed 2000 r.p.m. of the CAV control. That is, it isassumed that CAV characteristics 518 of 2000 r.p.m. shown by animaginary line are set. At the position of the innermost track T2, sincethe CAV characteristics 518 of 2000 r.p.m. coincide with 2000 r.p.m. ofthe 4-times speed CLV characteristics 512, the CD decoder can normallyoperate for the reading frequency of the read signal obtained by thespindle rotation by 2000 r.p.m. However, according to the CAVcharacteristics 518 of 2000 r.p.m., since the constant spindlerotational speed 2000 r.p.m. is always maintained in a range from theinner rim to the outer rim, the reading frequency of the CD which wasrecorded on the basis of the CLV control as a prerequisite correspondsto 2000 r.p.m. even at the position of the outermost track T0. Such aspeed is ten times as high as the rotational speed of 200 r.p.m. of thestandard CLV characteristics 510. Therefore, the read signal cannot beprocessed by the CD decoder corresponding to the 4-times speed.According to the invention, therefore, as shown in FIG. 47, the innerside is switched to the CAV control and the outer side is switched tothe CLV control.

FIG. 47 shows characteristics when the inner side corresponding to the4-times speed CLV characteristics 512 in FIG. 46 is set to the CAVcontrol. A switching point between the CAV control and the CLV controlis set to the track t1 at the intermediate position of the CD. In theintermediate track t1, as will be obviously understood from FIG. 46, thespeed is set to the spindle rotational speed 350 r.p.m. which is givenat a point 514 of the standard CLV characteristics 510. In the 4-timesspeed CLV characteristics 512, the standard rotational speed 350 r.p.m.of the intermediate track t1 is set to 1200 r.p.m. which is given at apoint 516. Therefore, in FIG. 47, the rotational speed in the CAVcontrol on the inner side than the intermediate track t1 is set to therotational speed 1200 r.p.m. of the intermediate track t1 in the 4-timesspeed CLV characteristics 512. Thus, the spindle rotational speed in arange from the innermost track T2 to the intermediate track t1 iscontrolled to the constant rotational speed 1200 r.p.m. as shown in CAVcharacteristics 520 of 1200 r.p.m. In a range from the intermediatetrack t1 to the outermost track T0, 4-times speed CLV characteristics524 are used as they are. Thus, in the CAV control of the spindle motorby the CAV characteristics 520 of 1200 r.p.m. on the inner side, sincesuch a speed lies within a speed range lower than the 4-times speed CLVcharacteristics 512 between the innermost track T2 and the intermediatetrack t1 shown in FIG. 46, a frequency of the read signal obtained bythe rotation of the spindle motor by the CAV characteristics 520 of 1200r.p.m. lies within an operating frequency of the CD decodercorresponding to the 4-times speed CLV control and it is possible toproperly cope with such a control.

FIG. 48 is a flowchart for the switching process between the CAV controland the CLV control according to the track position of FIG. 47. First,when a command interruption based on the read request of the CD from thehost computer is performed, the CAV/CLV switching control is activated.In step S1, a track address given by the command is read. In step S2, acheck is made to see if the designated track address is located on theinner side than the switching track t1 in FIG. 47. If YES, step S3follows and the CAV control of, for example, 2000 r.p.m. which isdetermined by the spindle rotational speed of the CAV control at theswitching position is executed. When the track address is located on theouter side, step S4 follows and, for example, the CLV control of the4-times speed is performed. In this manner, by setting the control modeto the CAV control on the inner side and to the CLV control on the outerside upon reproduction of the CD, when the CAV control is executed in arange up to the outer rim side, a situation such that the frequency ofthe read signal on the outer rim side increases and exceeds theprocessing ability of the CD decoder can be certainly prevented. By theCAV control on the inner rim side, the acceleration and deceleration ofthe spindle motor according to the track position, namely, the pickupposition are unnecessary. There is an advantage such that the electriccurrent consumption can be reduced. Particularly, in the CD-ROM which iscommercially available at present, the number of disks in which data hasbeen written to a region exceeding the intermediate position is actuallynot so large. Therefore, the reproducing operation of most of theCD-ROMs is executed by the CAV control on the inner side.

Although the switching between the CAV control and the CLV control ofthe CD mentioned above has been described with respect to the CAVcontrol corresponding to the 4-times speed of the CLV control as anexample, a switching control can be similarly executed with respect toan arbitrary-times speed of CD as necessary. Although the invention hasbeen described with respect to the case where the switching position wasset to the intermediate track as an example, the position of theswitching track can be also properly determined as necessary.

According to the invention as mentioned above, with respect to two kindsof media such as CD and MO cartridge, when the CD is loaded, theapparatus operates as a CD player and when the MO cartridge is loaded,the apparatus can operate as an MO drive. By merely providing a singleapparatus for the host such as a personal computer or the like, twokinds of different media such as CD and MO cartridge can be selectivelyused as necessary. As compared with the case where two media areseparately provided, the installing space and the costs can be reduced,and the ease of in use can be improved, or the like.

What is claimed is:
 1. An optical disk apparatus comprising:a commonprocessing unit for commonly executing both a process for a cartridgeenclosed medium and a process for an exposed medium which is not in acartridge, wherein said exposed medium is a non-hub compact disc and,when the compact disc is loaded into the optical disk apparatus, saidcommon processing unit operates as a CD player, said cartridge enclosedmedium is an optical disk cartridge enclosing an optical disk mediumwith a hub and said common processing unit operates as an optical diskdrive when the optical disk cartridge is loaded, said cartridge having afirst lateral width, said common processing unit comprising:a recordingand reproducing mechanism, enclosed in a main body of said optical diskapparatus, for commonly performing a reproduction of the compact discand a recording and a reproduction of the optical disk cartridge; aninserting/ejecting port for commonly inserting and ejecting the opticaldisk cartridge and a carrier, wherein prior to loading the compact discinto said main body, the compact disc is mounted upon said carrierhaving a second lateral width different from said first lateral width,said carrier being detachable from said main body; a circuit unit whichoperates as a CD player when the compact disc mounted on said carrier isloaded and operates as an optical disk drive when the optical diskcartridge is loaded; a path extending from said inserting/ejecting portto a location where said cartridge and said carrier have completedloading, said cartridge and said carrier moving along said path whilebeing loaded; a first set of guides generally extending along said pathfor guiding said cartridge along said path, and said first set of guidesbeing positioned to accommodate said first lateral width of saidcartridge; and a second set of guides generally extending along saidpath for guiding said carrier along said path, and said second set ofguides being positioned to accommodate said second lateral width of saidcarrier.
 2. An apparatus according to claim 1, wherein said recordingand reproducing mechanism has a pickup mechanism for commonly performingan optical reproduction of the compact disc and an optical recordingand/or reproduction of the optical disk.
 3. An apparatus according toclaim 1, including dimensional relations such that a thickness D2 of thecarrier for mounting the compact disc is thinner than a thickness D1 ofthe optical disk cartridge and that said second lateral width of saidcarrier is a width W2 and said first lateral width of the optical diskcartridge is a width W1, W2 being larger than W1, and an opening shapeof said inserting/ejecting port is set to a shape adapted to saiddimensional relations, thereby enabling the optical disk cartridge andsaid carrier to be inserted to a predetermined position of saidinserting/ejecting port.
 4. An apparatus according to claim 1, whereinsaid inserting/ejecting port has a stairway opening shape in which acartridge opening portion having a thickness D1 and a lateral width W1generally equal to said first lateral width of said optical diskcartridge and a carrier opening portion having a thickness D2 and alateral width W2 generally equal to said second lateral width of saidcarrier are synthesized so as to make center positions in the lateralwidth directions coincide.
 5. An apparatus according to claim 3, whereinsaid inserting/ejecting port has a stairway opening shape having astairway portion of about 1 mm in the thickness direction.
 6. Anapparatus according to claim 4, wherein the cartridge opening portionhaving the thickness D1 and width W1 of said optical disk cartridge andthe carrier opening portion having the thickness D2 and width W2 of saidcarrier are formed so as to make the center positions in the lateralwidth direction coincide by an arrangement of a guide member for anopening portion having the thickness D1 of said optical disk cartridgeand the lateral width W2 of said carrier.
 7. An apparatus according toclaim 1, wherein the optical disk cartridge is a magneto-optical diskcartridge of 3.5 inches based on the ISO.
 8. An apparatus according toclaim 1, wherein the compact disc is a compact disc of 120 mm for a readonly memory or a compact disc of 120 mm for digital audio.
 9. Anapparatus according to claim 1, wherein the compact disc is a compactdisc of 80 mm for digital audio.
 10. An apparatus according to claim 1,wherein the compact disc is a digital versatile disc.
 11. An apparatusaccording to claim 1, wherein said first set of guides includes planarmembers, rollers and spring biased positioning knobs.
 12. An apparatusaccording to claim 1, wherein said second set of guides includes planarmembers, rollers and at least one spring.
 13. An optical disk apparatuswhich is connected to a controller and performs an access to informationstored on an optical disk medium, comprising:a supporting member forrotatably supporting a first optical disk medium enclosed in a cartridgehaving a first lateral width and a second optical disk medium mounted ona carrier having a second lateral width, wherein said carrier isdetachable from said optical disk apparatus; an inserting/ejecting port;a loading mechanism for loading said cartridge and said carrier to saidoptical disk apparatus; a signal processing unit for optically readingout the information stored on said loaded optical disk medium andconverting said information into an electric signal; a rotation controlunit for controlling a rotation of said supporting means; and aninterface control unit for performing an interface control with saidcontroller; a path extending from said inserting/ejecting port to alocation where said cartridge and said carrier have completed loading,said cartridge and said carrier moving along said path while beingloaded; a first set of guides generally extending along said path forguiding said cartridge along said path, and said first set of guidesbeing positioned to accommodate said first lateral width of saidcartridge; and a second set of guides generally extending along saidpath for guiding said carrier along said path, and said second set ofguides being positioned to accommodate said second lateral width of saidcarrier.
 14. An optical disk apparatus, comprising:an insertion andejection port for a cartridge and a carrier; a common processing unitthat performs processes on a medium enclosed in said cartridge and anexposed medium mounted on said carrier, said cartridge having a firstwidth, and said carrier conveying said exposed medium to said commonprocessing unit and holding said exposed medium during an insertion to,and an ejection from, the optical disk apparatus, said carrier beingdetachable from the optical disk apparatus and having a second widthdifferent from said first width, and said insertion/ejection portconfigured and designed to accommodate both said cartridge of said firstwidth and said carrier of said second width; a path extending from saidinserting/ejecting port to a location where said cartridge and saidcarrier have completed loading, said cartridge and said carrier movingalong said path while being loaded; a first set of guides generallyextending along said path for guiding said cartridge along said path,and said first set of guides being positioned to accommodate said firstlateral width of said cartridge; and a second set of guides generallyextending along said path for guiding said carrier along said path, andsaid second set of guides being positioned to accommodate said secondlateral width of said carrier.
 15. An apparatus according to claim 14,wherein said cartridge enclosed medium is a medium with a hub and saidexposed medium is a non-hub medium.
 16. An apparatus according to claim15, wherein said exposed medium is a compact disc and when said compactdisc is loaded, said common processing unit operates as a CD player,saidcartridge enclosed medium is an optical disk cartridge enclosing anoptical disk medium with a hub, and when said optical disk cartridge isloaded, said common processing unit operates as a optical disk drive.17. An apparatus according to claim 16, wherein said common processingunit further includes:an apparatus main body defining saidinserting/ejecting port; a recording and reproducing mechanism, enclosedin said apparatus main body, for commonly performing a reproduction ofsaid compact disc and a recording and a reproduction of said opticaldisk cartridge; and a circuit unit which operates as a CD player whenthe compact disk is loaded and operates as an optical disk drive whensaid optical disk cartridge is loaded by said carrier.
 18. An apparatusaccording to claim 14, wherein said recording and reproducing mechanismhas a pickup mechanism for commonly performing an optical reproductionof the compact disc and an optical recording and/or reproduction of theoptical disk.
 19. An apparatus according to claim 14, includingdimensional relations such that a thickness D2 of the carrier formounting the compact disc is thinner than a thickness D1 of the opticaldisk cartridge and said second width of said carrier for mounting thecompact disc is larger than said first width of the optical diskcartridge, and an opening shape of said insertion/ejection port is setto a shape adapted to said dimensional relations, thereby enabling theoptical disk cartridge and said carrier to be inserted to apredetermined position of said insertion/ejection port.
 20. An apparatusaccording to claim 14, wherein said inserting/ejecting port has astairway opening shape in which a cartridge opening portion having athickness D1 and a width W1 generally equal to said first width of saidoptical disk cartridge and a carrier opening portion having a thicknessD2 and a width W2 generally equal to said second width of said carrierare synthesized so as to make center positions in the lateral widthdirections coincide.
 21. An apparatus according to claim 14, whereinsaid insertion/ejection port has a stairway opening shape having astairway portion of about 1 mm in the thickness direction.
 22. Anapparatus according to claim 14, wherein the cartridge opening portionhaving a thickness D1 and said first width of said optical diskcartridge and the carrier opening portion having the thickness D2 andsaid second width of said carrier are formed so as to make the centerpositions in the lateral width direction coincide by an arrangement of aguide member for an opening portion having the thickness D1 of saidoptical disk cartridge and the second lateral width of said carrier. 23.An apparatus according to claim 14, wherein the optical disk cartridgeis a magneto-optical disk cartridge of 3.5 inches based on the ISO. 24.An apparatus according to claim 14, wherein the compact disc is acompact disc of 120 mm for a read only memory or a compact disc of 120mm for digital audio.
 25. An apparatus according to claim 14, whereinthe compact disc is a compact disc of 80 mm for digital audio.
 26. Anapparatus according to claim 14, wherein the compact disc is a digitalversatile disc.
 27. An apparatus according to claim 14, wherein saidfirst set of guides includes planar members, rollers and spring biasedpositioning knobs.
 28. An apparatus according to claim 14, wherein saidsecond set of guides includes planar members, rollers and at least onespring.